# Vampire number

Vampire number
You are encouraged to solve this task according to the task description, using any language you may know.

A vampire number is a natural number with an even number of digits, that can be factored into two integers. These two factors are called the fangs, and must have the following properties:

• they each contain half the number of the digits of the original number
• together they consist of exactly the same digits as the original number
• at most one of them has a trailing zero

An example of a Vampire number and its fangs: ` 1260 : (21, 60) `

1. Print the first 25 Vampire numbers and their fangs.
2. Check if the following numbers are Vampire numbers and, if so, print them and their fangs:

` 16758243290880, 24959017348650, 14593825548650 `

Note that a Vampire number can have more than one pair of fangs.

## AutoHotkey

The following code should work for older (1.0.*) AHK versions as well:

`SetBatchLines -1 ; used to improve performance; (you can make it much faster by removing the informative tooltips) ;********************; CONFIG;********************StartingNumber := 10NumberLimit := 126030CounterLimit := 25 ; calculations stop when one of these limits is reachedAdditionalNumbers := "16758243290880,24959017348650,14593825548650";******************** CurrentCounter := 0, CurrentNumber := StartingNumber Loop  {    if !Mod(A_Index,75) ; informative tooltip (every 75 calculations, to avoid slowing down)        ToolTip, % "Checking numbers...`nNumber: " CurrentNumber            . "/" NumberLimit "`nFound: " CurrentCounter "/" CounterLimit    if ( CurrentCounter >= CounterLimit ) || ( CurrentNumber >= NumberLimit )        Break    if Mod(StrLen(CurrentNumber),2)        CurrentNumber *= 10    else if ( ( CurrentResult := GetFangs(CurrentNumber) ) <> "" )        Output .= "`n" CurrentNumber ":`t" CurrentResult, CurrentCounter++    CurrentNumber++}ToolTip ; hide informative tooltip MsgBox % SubStr(Output,2) ; show output (first part) Output := ""Loop, Parse, AdditionalNumbers, % ","{    ToolTip, % "Getting fangs for " A_LoopField " ..." ; informative tooltip    Output .= "`n" A_LoopField ":`n`t" GetFangs(A_LoopField) "`n"}ToolTip ; hide informative tooltip MsgBox % SubStr(Output,2) ; show output (second part - additional numbers)ExitApp ;---------------------------------------------------------------------------------- CharSorter(Input) { ; required by GetFangs()    Loop, Parse, Input        Output .= A_LoopField "`n"    Sort, Output    StringReplace, Output, Output, % "`n",, All    Return Output} ;---------------------------------------------------------------------------------- GetFangs(CurrentNumber) { ; requires CharSorter()    ResultIndex := 1    Length := StrLen(CurrentNumber)    Power := (Length//2)-1    if Mod(Length,2) OR !Power        Return ""    NumberLimit := Floor(Sqrt(CurrentNumber))    Lower := 10 ** Power    Loop, % NumberLimit - Lower {        if !Mod(CurrentNumber,Lower) {            FactorTwo := CurrentNumber//Lower            if ( !Mod(Lower,10) && !Mod(FactorTwo,10) )                Return ""            Check := CharSorter( Lower . FactorTwo )            if (CharSorter(CurrentNumber) = Check) && (StrLen(Lower) = StrLen(FactorTwo))                Output .= "`n`t[" Lower "," FactorTwo "]"        }        Lower++    }    Return SubStr(Output,3) ; 3 = 1 + length of "`n`t"}`
Output:
```1260:	[21,60]
1395:	[15,93]
1435:	[35,41]
1530:	[30,51]
1827:	[21,87]
2187:	[27,81]
6880:	[80,86]
102510:	[201,510]
104260:	[260,401]
105210:	[210,501]
105264:	[204,516]
105750:	[150,705]
108135:	[135,801]
110758:	[158,701]
115672:	[152,761]
116725:	[161,725]
117067:	[167,701]
118440:	[141,840]
123354:	[231,534]
124483:	[281,443]
125248:	[152,824]
125433:	[231,543]
125460:	[204,615]
[246,510]
125500:	[251,500]
126027:	[201,627]
------------------------------------
16758243290880:
[1982736,8452080]
[2123856,7890480]
[2751840,6089832]
[2817360,5948208]

24959017348650:
[2947050,8469153]
[2949705,8461530]
[4125870,6049395]
[4129587,6043950]
[4230765,5899410]

14593825548650:```

## Bracmat

`( ( vampire  =   N len R fangsList    .   !arg:@(?N:? [?len)      & 1/2*!len:~/:?len      & ( R        =     len numpart left right allowed fangs rdigits            , tried digit untried head tail found          .   !arg:(?len.?left.?numpart.?allowed)            & :?found            & (   !len:>0                & ( @( !numpart                     :   ?tried                         ( #%@?digit                         & !allowed:?head !digit ?tail                         & !head !tail:?allowed                         )                         ( ?untried                         &     R                             \$ ( !len+-1                               . 10*!left+!digit                               . str\$(!tried !untried)                               . 0 1 2 3 4 5 6 7 8 9                               )                           : ?fangs                         & !found !fangs:?found                         & ~                         )                     )                  | !found                  )              |   !N*!left^-1:~/?right:~<!left:?rdigits                & (!left*1/10:/|!right*1/10:/)                & ( @( !numpart                     :   ?                         ( #%@?digit ?                         & @(!rdigits:?head !digit ?tail)                         & str\$(!head !tail):?rdigits                         & ~                         )                     )                  | !rdigits:&(!left,!right)                  )              )        )      &   R\$(!len.0.!N.1 2 3 4 5 6 7 8 9)        : (           |   ?fangsList            & out\$(!N !fangsList)            & 1+!count:?count          )  )& 0:?count& 10:?i& 16758243290880 24959017348650 14593825548650:?bignums&   whl  ' ( ( vampire\$!i&1+!i:?i      | !i*10:?i      )    & (!count:<25|!bignums:%?i ?bignums)    ));`

Output:

```1260 (21,60)
1395 (15,93)
1435 (35,41)
1530 (30,51)
1827 (21,87)
2187 (27,81)
6880 (80,86)
102510 (201,510)
104260 (260,401)
105210 (210,501)
105264 (204,516)
105750 (150,705)
108135 (135,801)
110758 (158,701)
115672 (152,761)
116725 (161,725)
117067 (167,701)
118440 (141,840)
120600 (201,600)
123354 (231,534)
124483 (281,443)
125248 (152,824)
125433 (231,543)
125460 (246,510) (204,615)
125500 (251,500)
16758243290880
(1982736,8452080)
(2123856,7890480)
(2751840,6089832)
(2817360,5948208)
24959017348650
(2949705,8461530)
(2947050,8469153)
(4230765,5899410)
(4129587,6043950)
(4125870,6049395)```

## C

`#include <stdio.h>#include <stdlib.h>#include <stdint.h>#include <math.h> typedef uint64_t xint;typedef unsigned long long ull; xint tens[20]; inline xint max(xint a, xint b) { return a > b ? a : b; }inline xint min(xint a, xint b) { return a < b ? a : b; }inline int ndigits(xint x){	int n = 0;	while (x) n++, x /= 10;	return n;} inline xint dtally(xint x){	xint t = 0;	while (x) t += 1<<((x%10) * 6), x /= 10; 	return t;} int fangs(xint x, xint *f){	int n = 0;	int nd = ndigits(x);	if (nd & 1) return 0;	nd /= 2; 	xint lo, hi;	lo = max(tens[nd-1], (x + tens[nd] - 2)/ (tens[nd] - 1));	hi = min(x / lo, sqrt(x)); 	xint a, b, t = dtally(x);	for (a = lo; a <= hi; a++) {		b = x / a;		if (a * b == x && ((a%10) || (b%10)) && t == dtally(a) + dtally(b))			f[n++] = a;	} 	return n;} void show_fangs(xint x, xint *f, xint cnt){	printf("%llu", (ull)x);	int i;	for (i = 0; i < cnt; i++)		printf(" = %llu x %llu", (ull)f[i], (ull)(x / f[i]));	putchar('\n');} int main(void){	int i, j, n;	xint x, f[16], bigs[] = {16758243290880ULL, 24959017348650ULL, 14593825548650ULL, 0}; 	tens[0] = 1;	for (i = 1; i < 20; i++)		tens[i] = tens[i-1] * 10; 	for (x = 1, n = 0; n < 25; x++) {		if (!(j = fangs(x, f))) continue;		printf("%2d: ", ++n);		show_fangs(x, f, j);	} 	putchar('\n');	for (i = 0; bigs[i]; i++) {		if ((j = fangs(bigs[i], f)))			show_fangs(bigs[i], f, j);		else			printf("%llu is not vampiric\n", (ull)bigs[i]);	} 	return 0;}`
``` 1: 1260 = 21 x 60
2: 1395 = 15 x 93
3: 1435 = 35 x 41
4: 1530 = 30 x 51
5: 1827 = 21 x 87
6: 2187 = 27 x 81
7: 6880 = 80 x 86
8: 102510 = 201 x 510
9: 104260 = 260 x 401
10: 105210 = 210 x 501
11: 105264 = 204 x 516
12: 105750 = 150 x 705
13: 108135 = 135 x 801
14: 110758 = 158 x 701
15: 115672 = 152 x 761
16: 116725 = 161 x 725
17: 117067 = 167 x 701
18: 118440 = 141 x 840
19: 120600 = 201 x 600
20: 123354 = 231 x 534
21: 124483 = 281 x 443
22: 125248 = 152 x 824
23: 125433 = 231 x 543
24: 125460 = 204 x 615 = 246 x 510
25: 125500 = 251 x 500

16758243290880 = 1982736 x 8452080 = 2123856 x 7890480 = 2751840 x 6089832 = 2817360 x 5948208
24959017348650 = 2947050 x 8469153 = 2949705 x 8461530 = 4125870 x 6049395 = 4129587 x 6043950 = 4230765 x 5899410
14593825548650 is not vampiric```

## C#

Translation of: C
`using System; namespace RosettaVampireNumber{    class Program    {        static void Main(string[] args)        {            int i, j, n;            ulong x;            var f = new ulong[16];            var bigs = new ulong[] { 16758243290880UL, 24959017348650UL, 14593825548650UL, 0 };            ulong[] tens = new ulong[20];            tens[0] = 1;            for (i = 1; i < 20; i++)                tens[i] = tens[i - 1] * 10;             for (x = 1, n = 0; n < 25; x++)            {                if ((j = fangs(x, f, tens)) == 0) continue;                Console.Write(++n + ": ");                show_fangs(x, f, j);            }             Console.WriteLine();            for (i = 0; bigs[i] > 0 ; i++)            {                if ((j = fangs(bigs[i], f, tens)) > 0)                    show_fangs(bigs[i], f, j);                else                    Console.WriteLine(bigs[i] + " is not vampiric.");            }            Console.ReadLine();        }         private static void show_fangs(ulong x, ulong[] f, int cnt)        {            Console.Write(x);             int i;            for (i = 0; i < cnt; i++)                Console.Write(" = " + f[i] + " * " + (x / f[i]));            Console.WriteLine();        }         private static int fangs(ulong x, ulong[] f, ulong[] tens)        {            int n = 0;            int nd = ndigits(x);            if ((nd & 1) > 0) return 0;            nd /= 2;             ulong lo, hi;            lo = Math.Max(tens[nd - 1], (x + tens[nd] - 2) / (tens[nd] - 1));            hi = Math.Min(x / lo, (ulong) Math.Sqrt(x));             ulong a, b, t = dtally(x);            for (a = lo; a <= hi; a++)            {                b = x / a;                if (a * b == x && ((a % 10) > 0 || (b % 10) > 0) && t == dtally(a) + dtally(b))                    f[n++] = a;            }             return n;        }         private static ulong dtally(ulong x)        {            ulong t = 0;            while (x > 0)            {                t += 1UL << (int)((x % 10) * 6);                x /= 10;            }             return t;        }         private static int ndigits(ulong x)        {            int n = 0;            while (x > 0)            {                n++;                x /= 10;            }            return n;        }    }}`
Output:
```1: 1260 = 21 * 60
2: 1395 = 15 * 93
3: 1435 = 35 * 41
4: 1530 = 30 * 51
5: 1827 = 21 * 87
6: 2187 = 27 * 81
7: 6880 = 80 * 86
8: 102510 = 201 * 510
9: 104260 = 260 * 401
10: 105210 = 210 * 501
11: 105264 = 204 * 516
12: 105750 = 150 * 705
13: 108135 = 135 * 801
14: 110758 = 158 * 701
15: 115672 = 152 * 761
16: 116725 = 161 * 725
17: 117067 = 167 * 701
18: 118440 = 141 * 840
19: 120600 = 201 * 600
20: 123354 = 231 * 534
21: 124483 = 281 * 443
22: 125248 = 152 * 824
23: 125433 = 231 * 543
24: 125460 = 204 * 615 = 246 * 510
25: 125500 = 251 * 500

16758243290880 = 1982736 * 8452080 = 2123856 * 7890480 = 2751840 * 6089832 = 2817360 * 5948208
24959017348650 = 2947050 * 8469153 = 2949705 * 8461530 = 4125870 * 6049395 = 4129587 * 6043950 = 4230765 * 5899410
14593825548650 is not vampiric.
```

## C++

`#include <vector>#include <utility>#include <algorithm>#include <iostream>#include <sstream>#include <string>#include <cmath> bool isVampireNumber( long number, std::vector<std::pair<long, long> > & solution ) {   std::ostringstream numberstream ;   numberstream << number ;   std::string numberstring( numberstream.str( ) ) ;   std::sort ( numberstring.begin( ) , numberstring.end( ) ) ;   int fanglength = numberstring.length( ) / 2 ;   long start = static_cast<long>( std::pow( 10 , fanglength - 1 ) ) ;   long end = sqrt(number) ;   for ( long i = start ; i <= end ; i++ ) {       if ( number % i == 0 ) {	 long quotient = number / i ;	 if ( ( i % 10 == 0 ) && ( quotient % 10 == 0 ) ) 	    continue ;	 numberstream.str( "" ) ; //clear the number stream	 numberstream << i << quotient ;	 std::string divisorstring ( numberstream.str( ) ) ;         std::sort ( divisorstring.begin( ) , divisorstring.end( ) ) ;	 if ( divisorstring == numberstring ) {	    std::pair<long , long> divisors = std::make_pair( i, quotient ) ;	    solution.push_back( divisors ) ;	 }      }   }   return !solution.empty( ) ;} void printOut( const std::pair<long, long> & solution ) {   std::cout << "[ " << solution.first << " , " << solution.second << " ]" ;} int main( ) {   int vampireNumbersFound = 0 ;   std::vector<std::pair<long , long> > solutions ;   double i = 1.0 ;   while ( vampireNumbersFound < 25 ) {      long start = static_cast<long>( std::pow( 10 , i ) ) ;      long end = start * 10 ;      for ( long num = start ; num < end ; num++ ) {	 if ( isVampireNumber( num , solutions ) ) {            vampireNumbersFound++ ;	    std::cout << vampireNumbersFound << " :" << num << " is a vampire number! These are the fangs:\n" ;	    std::for_each( solutions.begin( ) , solutions.end( ) , printOut ) ;	    std::cout << "\n_______________" << std::endl ;	    solutions.clear( ) ;	    	    if ( vampireNumbersFound == 25 ) 	       break ;	 }      }      i += 2.0 ;   }   std::vector<long> testnumbers ;   testnumbers.push_back( 16758243290880 ) ;   testnumbers.push_back( 24959017348650 ) ;   testnumbers.push_back( 14593825548650 ) ;   for ( std::vector<long>::const_iterator svl = testnumbers.begin( ) ; 	 svl != testnumbers.end( ) ; svl++ ) {      if ( isVampireNumber( *svl , solutions ) ) {	 std::cout << *svl << " is a vampire number! The fangs:\n" ;	 std::for_each( solutions.begin( ) , solutions.end( ) , printOut ) ;	 std::cout << std::endl ;	 solutions.clear( ) ;      } else {	 std::cout << *svl << " is not a vampire number!" << std::endl ;      }   }   return 0 ;}`
Output:
```1 :1260 is a vampire number! These are the fangs:
[ 21 , 60 ]
_______________
2 :1395 is a vampire number! These are the fangs:
[ 15 , 93 ]
_______________
3 :1435 is a vampire number! These are the fangs:
[ 35 , 41 ]
_______________
4 :1530 is a vampire number! These are the fangs:
[ 30 , 51 ]
_______________
5 :1827 is a vampire number! These are the fangs:
[ 21 , 87 ]
_______________
6 :2187 is a vampire number! These are the fangs:
[ 27 , 81 ]
_______________
7 :6880 is a vampire number! These are the fangs:
[ 80 , 86 ]
_______________
8 :102510 is a vampire number! These are the fangs:
[ 201 , 510 ]
_______________
9 :104260 is a vampire number! These are the fangs:
[ 260 , 401 ]
_______________
10 :105210 is a vampire number! These are the fangs:
[ 210 , 501 ]
_______________
11 :105264 is a vampire number! These are the fangs:
[ 204 , 516 ]
_______________
12 :105750 is a vampire number! These are the fangs:
[ 150 , 705 ]
_______________
13 :108135 is a vampire number! These are the fangs:
[ 135 , 801 ]
_______________
14 :110758 is a vampire number! These are the fangs:
[ 158 , 701 ]
_______________
15 :115672 is a vampire number! These are the fangs:
[ 152 , 761 ]
_______________
16 :116725 is a vampire number! These are the fangs:
[ 161 , 725 ]
_______________
17 :117067 is a vampire number! These are the fangs:
[ 167 , 701 ]
_______________
18 :118440 is a vampire number! These are the fangs:
[ 141 , 840 ]
_______________
19 :120600 is a vampire number! These are the fangs:
[ 201 , 600 ]
_______________
20 :123354 is a vampire number! These are the fangs:
[ 231 , 534 ]
_______________
21 :124483 is a vampire number! These are the fangs:
[ 281 , 443 ]
_______________
22 :125248 is a vampire number! These are the fangs:
[ 152 , 824 ]
_______________
23 :125433 is a vampire number! These are the fangs:
[ 231 , 543 ]
_______________
24 :125460 is a vampire number! These are the fangs:
[ 204 , 615 ][ 246 , 510 ]
_______________
25 :125500 is a vampire number! These are the fangs:
[ 251 , 500 ]
_______________
16758243290880 is a vampire number! The fangs:
[ 1982736 , 8452080 ][ 2123856 , 7890480 ][ 2751840 , 6089832 ][ 2817360 , 5948208 ]
24959017348650 is a vampire number! The fangs:
[ 2947050 , 8469153 ][ 2949705 , 8461530 ][ 4125870 , 6049395 ][ 4129587 , 6043950 ][ 4230765 , 5899410 ]
14593825548650 is not a vampire number!
```

## Clojure

`(defn factor-pairs [n]  (for [x (range 2 (Math/sqrt n))        :when (zero? (mod n x))]    [x (quot n x)])) (defn fangs [n]  (let [dlen (comp count str)        half (/ (dlen n) 2)        halves? #(apply = (cons half (map dlen %)))        digits  #(sort (apply str %))]    (filter #(and (halves? %)                  (= (sort (str n)) (digits %)))            (factor-pairs n)))) (defn vampiric? [n]  (let [fangs (fangs n)]    (if (empty? fangs) nil [n fangs]))) (doseq [n (take 25 (keep vampiric? (range)))]  (prn n)) (doseq [n [16758243290880, 24959017348650, 14593825548650]]  (println (or (vampiric? n) (str n " is not vampiric."))))`

## Common Lisp

`(defun trailing-zerop (number)  "Is the lowest digit of `number' a 0"  (zerop (rem number 10))) (defun integer-digits (integer)  "Return the number of digits of the `integer'"  (assert (integerp integer))  (length (write-to-string integer))) (defun paired-factors (number)  "Return a list of pairs that are factors of `number'"  (loop    :for candidate :from 2 :upto (sqrt number)    :when (zerop (mod number candidate))      :collect (list candidate (/ number candidate)))) (defun vampirep (candidate &aux                             (digits-of-candidate (integer-digits candidate))                             (half-the-digits-of-candidate (/ digits-of-candidate                                                              2)))  "Is the `candidate' a vampire number?"  (remove-if #'(lambda (pair)                 (> (length (remove-if #'null (mapcar #'trailing-zerop pair)))                     1))              (remove-if-not #'(lambda (pair)                                (string= (sort (copy-seq (write-to-string candidate))                                               #'char<)                                         (sort (copy-seq (format nil "~A~A" (first pair) (second pair)))                                               #'char<)))                            (remove-if-not #'(lambda (pair)                                               (and (eql (integer-digits (first pair))                                                         half-the-digits-of-candidate)                                                    (eql (integer-digits (second pair))                                                         half-the-digits-of-candidate)))                                           (paired-factors candidate))))) (defun print-vampire (candidate fangs &optional (stream t))  (format stream          "The number ~A is a vampire number with fangs: ~{ ~{~A~^, ~}~^; ~}~%"          candidate          fangs)) ;; Print the first 25 vampire numbers (loop  :with count := 0  :for candidate :from 0  :until (eql count 25)  :for fangs := (vampirep candidate)  :do     (when fangs       (print-vampire candidate fangs)       (incf count))) ;; Check if 16758243290880, 24959017348650, 14593825548650 are vampire numbers (dolist (candidate '(16758243290880 24959017348650 14593825548650))  (let ((fangs (vampirep candidate)))    (when fangs      (print-vampire candidate fangs)))) `
Output:
```The number 1260 is a vampire number with fangs:  21, 60
The number 1395 is a vampire number with fangs:  15, 93
The number 1435 is a vampire number with fangs:  35, 41
The number 1530 is a vampire number with fangs:  30, 51
The number 1827 is a vampire number with fangs:  21, 87
The number 2187 is a vampire number with fangs:  27, 81
The number 6880 is a vampire number with fangs:  80, 86
The number 102510 is a vampire number with fangs:  201, 510
The number 104260 is a vampire number with fangs:  260, 401
The number 105210 is a vampire number with fangs:  210, 501
The number 105264 is a vampire number with fangs:  204, 516
The number 105750 is a vampire number with fangs:  150, 705
The number 108135 is a vampire number with fangs:  135, 801
The number 110758 is a vampire number with fangs:  158, 701
The number 115672 is a vampire number with fangs:  152, 761
The number 116725 is a vampire number with fangs:  161, 725
The number 117067 is a vampire number with fangs:  167, 701
The number 118440 is a vampire number with fangs:  141, 840
The number 120600 is a vampire number with fangs:  201, 600
The number 123354 is a vampire number with fangs:  231, 534
The number 124483 is a vampire number with fangs:  281, 443
The number 125248 is a vampire number with fangs:  152, 824
The number 125433 is a vampire number with fangs:  231, 543
The number 125460 is a vampire number with fangs:  204, 615;  246, 510
The number 125500 is a vampire number with fangs:  251, 500

The number 16758243290880 is a vampire number with fangs:  1982736, 8452080;  2123856, 7890480;  2751840, 6089832;  2817360, 5948208
The number 24959017348650 is a vampire number with fangs:  2947050, 8469153;  2949705, 8461530;  4125870, 6049395;  4129587, 6043950;  4230765, 5899410
The number 16758243290880 is a vampire number with fangs:  1982736, 8452080;  2123856, 7890480;  2751840, 6089832;  2817360, 5948208
The number 24959017348650 is a vampire number with fangs:  2947050, 8469153;  2949705, 8461530;  4125870, 6049395;  4129587, 6043950;  4230765, 5899410
```

## D

The two versions show two styles of D code: compact script-like mostly-functional code, and efficient lower-level code.

### High-Level Version

Translation of: Clojure

(Runtime about 1.34 seconds with dmd.)

`import std.stdio, std.range, std.algorithm, std.typecons, std.conv; auto fangs(in long n) pure nothrow @safe {    auto pairs = iota(2, cast(int)(n ^^ 0.5)) // n.isqrt                 .filter!(x => !(n % x)).map!(x => [x, n / x]);    enum dLen = (in long x) => x.text.length;    immutable half = dLen(n) / 2;    enum halvesQ = (long[] p) => p.all!(u => dLen(u) == half);    enum digits = (long[] p) => dtext(p[0], p[1]).dup.sort();    const dn = n.to!(dchar[]).sort();    return tuple(n, pairs.filter!(p => halvesQ(p) && dn == digits(p)));} void main() {    foreach (v; int.max.iota.map!fangs.filter!q{ !a[1].empty }                .take(25).chain([16758243290880, 24959017348650,                                 14593825548650].map!fangs))        writefln("%d: (%(%(%s %)) (%))", v[]);}`
Output:
```1260: (21 60)
1395: (15 93)
1435: (35 41)
1530: (30 51)
1827: (21 87)
2187: (27 81)
6880: (80 86)
102510: (201 510)
104260: (260 401)
105210: (210 501)
105264: (204 516)
105750: (150 705)
108135: (135 801)
110758: (158 701)
115672: (152 761)
116725: (161 725)
117067: (167 701)
118440: (141 840)
120600: (201 600)
123354: (231 534)
124483: (281 443)
125248: (152 824)
125433: (231 543)
125460: (204 615) (246 510)
125500: (251 500)
16758243290880: (1982736 8452080) (2123856 7890480) (2751840 6089832) (2817360 5948208)
24959017348650: (2947050 8469153) (2949705 8461530) (4125870 6049395) (4129587 6043950) (4230765 5899410)
14593825548650: ()```

### Fast Version

Translation of: C

(Runtime about 0.27 seconds with dmd, about 0.25 seconds with ldc2 compilers.)

`import std.stdio, std.math, std.algorithm, std.array, std.traits; T[N] pows(T, size_t N)() pure nothrow @safe @nogc {    typeof(return) result;    result[0] = 1;    foreach (immutable i, ref r; result[1 .. \$])        r = result[i] * 10;    return result;} __gshared immutable tenPowsU = pows!(uint, 10);__gshared immutable tenPowsUL = pows!(ulong, 20); size_t nDigits(T)(in T x) pure nothrow @safe @nogc {    Unqual!T y = x;    size_t n = 0;    while (y) {        n++;        y /= 10;    }    return n;} T dTally(T)(in T x) pure nothrow @safe @nogc {    Unqual!T y = x;    T t = 0;    while (y) {        t += 1 << ((y % 10) * 6);        y /= 10;    }    return t;} T[] fangs(T)(in T x, T[] f)pure nothrow @safe @nogc if (is(T == uint) || is(T == ulong)) {    alias tenPows = Select!(is(T == ulong), tenPowsUL, tenPowsU);     immutable nd0 = nDigits(x);    if (nd0 & 1)        return null;    immutable nd = nd0 / 2;     immutable lo = max(tenPows[nd - 1],                       (x + tenPows[nd] - 2) / (tenPows[nd] - 1));    immutable hi = min(x / lo, cast(T)sqrt(real(x)));    immutable t = x.dTally;     size_t n = 0;    foreach (immutable a; lo .. hi + 1) {        immutable b = x / a;        if (a * b == x            && (a % 10 || b % 10)            && t == (a.dTally + b.dTally)) {            f[n] = a;            n++;        }    }     return f[0 .. n];} void showFangs(T)(in T x, in T[] fs) {    x.write;    foreach (immutable fi; fs)        writef(" = %d x %d", fi, x / fi);    writeln;} void main() {    uint[16] fu;    for (uint x = 1, n = 0; n < 25; x++) {        const fs = fangs(x, fu);        if (fs.empty)            continue;        n++;        writef("%2d: ", n);        showFangs(x, fs);    }    writeln;     static immutable ulong[3] bigs = [16_758_243_290_880UL,                                      24_959_017_348_650UL,                                      14_593_825_548_650UL];    ulong[fu.length] ful;    foreach (immutable bi; bigs) {        const fs = fangs(bi, ful);        if (fs.empty)            writeln(bi, " is not vampiric");        else            showFangs(bi, fs);    }}`
Output:
``` 2: 1395 = 15 x 93
3: 1435 = 35 x 41
4: 1530 = 30 x 51
5: 1827 = 21 x 87
6: 2187 = 27 x 81
7: 6880 = 80 x 86
8: 102510 = 201 x 510
9: 104260 = 260 x 401
10: 105210 = 210 x 501
11: 105264 = 204 x 516
12: 105750 = 150 x 705
13: 108135 = 135 x 801
14: 110758 = 158 x 701
15: 115672 = 152 x 761
16: 116725 = 161 x 725
17: 117067 = 167 x 701
18: 118440 = 141 x 840
19: 120600 = 201 x 600
20: 123354 = 231 x 534
21: 124483 = 281 x 443
22: 125248 = 152 x 824
23: 125433 = 231 x 543
24: 125460 = 204 x 615 = 246 x 510
25: 125500 = 251 x 500

16758243290880 = 1982736 x 8452080 = 2123856 x 7890480 = 2751840 x 6089832 = 2817360 x 5948208
24959017348650 = 2947050 x 8469153 = 2949705 x 8461530 = 4125870 x 6049395 = 4129587 x 6043950 = 4230765 x 5899410
14593825548650 is not vampiric```

## Eiffel

` class	APPLICATION create	make feature 	fang_check (original, fang1, fang2: INTEGER_64): BOOLEAN			-- Are 'fang1' and 'fang2' correct fangs of the 'original' number?		require			original_positive: original > 0			fangs_positive: fang1 > 0 and fang2 > 0		local			original_length: INTEGER			fang, ori: STRING			sort_ori, sort_fang: SORTED_TWO_WAY_LIST [CHARACTER]		do			create sort_ori.make			create sort_fang.make			create ori.make_empty			create fang.make_empty			original_length := original.out.count // 2			if fang1.out.count /= original_length or fang2.out.count /= (original_length) then				Result := False			elseif fang1.out.ends_with ("0") and fang2.out.ends_with ("0") then				Result := False			else				across					1 |..| original.out.count as c				loop					sort_ori.extend (original.out [c.item])				end				across					sort_ori as o				loop					ori.extend (o.item)				end				across					1 |..| fang1.out.count as c				loop					sort_fang.extend (fang1.out [c.item])					sort_fang.extend (fang2.out [c.item])				end				across					sort_fang as f				loop					fang.extend (f.item)				end				Result := fang.same_string (ori)			end		ensure			fangs_right_length: Result implies original.out.count = fang1.out.count + fang2.out.count		end 	make                -- Uses fang_check to find vampire nubmers.		local			i, numbers: INTEGER			fang1, fang2: INTEGER_64			num: ARRAY [INTEGER_64]			math: DOUBLE_MATH		do			create math			from				i := 1000			until				numbers > 25			loop				if i.out.count \\ 2 = 0 then					from						fang1 := 10					until						fang1 >= math.sqrt (i)					loop						if (i \\ fang1 = 0) then							fang2 := i // fang1							if i \\ 9 = (fang1 + fang2) \\ 9 then								if fang1 * fang2 = i and fang1 <= fang2 and then fang_check (i, fang1, fang2) then									numbers := numbers + 1									io.put_string (i.out + ": " + fang1.out + " " + fang2.out)									io.new_line								end							end						end						fang1 := fang1 + 1					end				end				i := i + 1			end			num := <<16758243290880, 24959017348650, 14593825548650>>			across				num as n			loop				from					fang1 := 1000000				until					fang1 >= math.sqrt (n.item) + 1				loop					if (n.item \\ fang1 = 0) then						fang2 := (n.item // fang1)						if fang1 * fang2 = n.item and fang1 <= fang2 and then fang_check (n.item, fang1, fang2) then							io.put_string (n.item.out + ": " + fang1.out + " " + fang2.out + "%N")						end					end					fang1 := fang1 + 1				end			end		end end `
Output:
```1260: 21, 60
1395: 15, 93
1435: 35, 41
1530: 30, 51
1827: 21, 87
2187: 27, 81
6880: 80, 86
102510: 201, 510
104260: 260, 401
105210: 210, 501
105264: 204, 516
105750: 150, 705
108135: 135, 801
110758: 158, 701
115672: 152, 761
116725: 161, 725
117067: 167, 701
118440: 141, 840
120600: 201, 600
123354: 231, 534
124483: 281, 443
125248: 152, 824
125433: 231, 543
125460: 204, 615
125460: 246, 510
125500: 251, 500
126027: 201, 627
16758243290880: 1982736, 8452080
16758243290880: 2123856, 7890480
16758243290880: 2751840, 6089832
16758243290880: 2817360, 5948208
24959017348650: 2947050, 8469153
24959017348650: 2949705, 8461530
24959017348650: 4125870, 6049395
24959017348650: 4129587, 6043950
24959017348650: 4230765, 5899410
```

## Elixir

Works with: Elixir version 1.1+
`defmodule Vampire do  def factor_pairs(n) do    first = trunc(n / :math.pow(10, div(char_len(n), 2)))    last  = :math.sqrt(n) |> round    for i <- first .. last, rem(n, i) == 0, do: {i, div(n, i)}  end   def vampire_factors(n) do    if rem(char_len(n), 2) == 1 do      []    else      half = div(length(to_char_list(n)), 2)      sorted = Enum.sort(String.codepoints("#{n}"))      Enum.filter(factor_pairs(n), fn {a, b} ->        char_len(a) == half && char_len(b) == half &&        Enum.count([a, b], fn x -> rem(x, 10) == 0 end) != 2 &&        Enum.sort(String.codepoints("#{a}#{b}")) == sorted      end)    end  end   defp char_len(n), do: length(to_char_list(n))   def task do    Enum.reduce_while(Stream.iterate(1, &(&1+1)), 1, fn n, acc ->      case vampire_factors(n) do        [] -> {:cont, acc}        vf -> IO.puts "#{n}:\t#{inspect vf}"              if acc < 25, do: {:cont, acc+1}, else: {:halt, acc+1}      end    end)    IO.puts ""    Enum.each([16758243290880, 24959017348650, 14593825548650], fn n ->      case vampire_factors(n) do        [] -> IO.puts "#{n} is not a vampire number!"        vf -> IO.puts "#{n}:\t#{inspect vf}"      end    end)  endend Vampire.task`
Output:
```1260:	[{21, 60}]
1395:	[{15, 93}]
1435:	[{35, 41}]
1530:	[{30, 51}]
1827:	[{21, 87}]
2187:	[{27, 81}]
6880:	[{80, 86}]
102510:	[{201, 510}]
104260:	[{260, 401}]
105210:	[{210, 501}]
105264:	[{204, 516}]
105750:	[{150, 705}]
108135:	[{135, 801}]
110758:	[{158, 701}]
115672:	[{152, 761}]
116725:	[{161, 725}]
117067:	[{167, 701}]
118440:	[{141, 840}]
120600:	[{201, 600}]
123354:	[{231, 534}]
124483:	[{281, 443}]
125248:	[{152, 824}]
125433:	[{231, 543}]
125460:	[{204, 615}, {246, 510}]
125500:	[{251, 500}]

16758243290880:	[{1982736, 8452080}, {2123856, 7890480}, {2751840, 6089832}, {2817360, 5948208}]
24959017348650:	[{2947050, 8469153}, {2949705, 8461530}, {4125870, 6049395}, {4129587, 6043950}, {4230765, 5899410}]
14593825548650 is not a vampire number!
```

## Factor

`USING: combinators.short-circuit fry io kernel lists lists.lazy mathmath.combinatorics math.functions math.primes.factors math.statisticsmath.text.utils prettyprint sequences sets ;IN: rosetta-code.vampire-number : digits ( n -- m )    log10 floor >integer 1 + ; : same-digits? ( n n1 n2 -- ? )    [ 1 digit-groups ] [email protected] append [ histogram ] [email protected] = ;     : half-len-factors ( n -- seq )    [ divisors ] [ digits ] bi 2/ '[ digits _ = ] filter ; : same-digit-factors ( n -- seq )    dup half-len-factors 2 <combinations> [ first2 same-digits? ] with filter ; : under-two-trailing-zeros? ( seq -- ? )    [ 10 mod ] map [ 0 = ] count 2 < ; : tentative-fangs ( n -- seq )    same-digit-factors [ under-two-trailing-zeros? ] filter ; : fangs ( n -- seq )    [ tentative-fangs ] [ ] bi '[ product _ = ] filter ; : vampire? ( n -- ? )    { [ digits even? ] [ fangs empty? not ] } 1&& ; : first25 ( -- seq )    25 0 lfrom [ vampire? ] lfilter ltake list>array ; : .vamp-with-fangs ( n -- )    [ pprint bl ] [ fangs [ pprint bl ] each ] bi nl ; : part1 ( -- )    first25 [ .vamp-with-fangs ] each ; : part2 ( -- ) { 16758243290880 24959017348650 14593825548650 }    [ dup vampire? [ .vamp-with-fangs ] [ drop ] if ] each ; : main ( -- ) part1 part2 ; MAIN: main`
Output:
```1260 { 21 60 }
1395 { 15 93 }
1435 { 35 41 }
1530 { 30 51 }
1827 { 21 87 }
2187 { 27 81 }
6880 { 80 86 }
102510 { 201 510 }
104260 { 260 401 }
105210 { 210 501 }
105264 { 204 516 }
105750 { 150 705 }
108135 { 135 801 }
110758 { 158 701 }
115672 { 152 761 }
116725 { 161 725 }
117067 { 167 701 }
118440 { 141 840 }
120600 { 201 600 }
123354 { 231 534 }
124483 { 281 443 }
125248 { 152 824 }
125433 { 231 543 }
125460 { 204 615 } { 246 510 }
125500 { 251 500 }
16758243290880 { 1982736 8452080 } { 2123856 7890480 } { 2751840 6089832 } { 2817360 5948208 }
24959017348650 { 2947050 8469153 } { 2949705 8461530 } { 4125870 6049395 } { 4129587 6043950 } { 4230765 5899410 }
```

## FreeBASIC

`'Vampire numbers.'FreeBASIC version 24. Windows'Vampire.basFunction WithinString(n As Ulongint,f As Ulongint) As Integer    var m=Str(n),p=Str(f)    For z As Integer=0 To Len(p)-1        var i=Instr(m,Chr(p[z]))        If i Then            m=Mid(m,1,i-1)+Mid(m,i+1)        Else            Return 0        End If    Next z    Return -1End Function Sub AllFactors(N As Ulongint,factors() As Ulongint)     Dim As String Sn=Str(n)    Dim As Integer half=Len(sn)\2    Redim factors(1 To 1)    #macro bsort(array)    For p1 As Integer  = 1 To Ubound(array) - 1        For p2 As Integer  = p1 + 1 To Ubound(array)              If array(p1)>array(p2) Then Swap array(p1),array(p2)        Next p2    Next p1    #endmacro     Dim As Ulongint c    For i As Ulongint = 1 To Sqr(N)               If N Mod i=0 Then            If Len(Str(i))=half Then                If WithinString(N,i) Then                    c=c+1                    Redim Preserve factors(1 To c)                    factors(c)=i                End If            End If            If N <> i*i Then                 If Len(Str(n\i))=half Then                    If WithinString(N,n\i) Then                        c=c+1                        Redim Preserve factors(1 To c)                        factors(c)=n\i                    End If                End If            End If         End If     Next i    bsort(factors)End Sub Function VampireNumbers(N As Ulongint) As Integer    Dim As Integer flag    Dim As Ulongint LastFactor    Redim As Ulongint Factor()    AllFactors(N,Factor())    For p1 As Integer = 1 To Ubound(Factor)        For p2 As Integer=1 To Ubound(Factor)            If Factor(p1)*Factor(p2)=n Then                If Factor(p1) Mod 10<>0 Or Factor(p2) Mod 10 <>0 Then                     If WithinString(n,valulng(Str(Factor(p1))+Str(Factor(p2)))) Then                        If LastFactor=Factor(p2) Then Exit For,For                        flag=1                        Print n;": [";Factor(p1);",";Factor(p2);"]"                        LastFactor=Factor(p1)                    End If                End If            End If        Next p2    Next p1    If flag Then Return -1End Function '============== IMPLEMENT ==============================print "First 28 Vampire numbers"printPrint "Number: [fangs]"PrintDim As Ulongint n=1000Dim As Integer countDim As Double t1,t2t1=TimerDo    n=n+1    Var s=Str(n)    If Len(s) Mod 2<>0 Then n=n*10    If vampireNumbers(n) Then count=count+1Loop Until count=27 Printprint "Individual tests:"print'individual testsn=16758243290880ullIf Not vampirenumbers(n) Then Print n;": [returns no fangs]"Printn=24959017348650ullIf Not vampirenumbers(n) Then Print n;": [returns no fangs]"printn=14593825548650ullIf Not vampirenumbers(n) then print n;": [returns no fangs]"t2=TimerprintPrint "Completed in ";Print t2-t1;" Seconds"Sleep`
Output:
```First 28 Vampire numbers

Number: [fangs]

1260: [21,60]
1395: [15,93]
1435: [35,41]
1530: [30,51]
1827: [21,87]
2187: [27,81]
6880: [80,86]
102510: [201,510]
104260: [260,401]
105210: [210,501]
105264: [204,516]
105750: [150,705]
108135: [135,801]
110758: [158,701]
115672: [152,761]
116725: [161,725]
117067: [167,701]
118440: [141,840]
120600: [201,600]
123354: [231,534]
124483: [281,443]
125248: [152,824]
125433: [231,543]
125460: [204,615]
125460: [246,510]
125500: [251,500]
126027: [201,627]
126846: [261,486]

Individual tests:

16758243290880: [1982736,8452080]
16758243290880: [2123856,7890480]
16758243290880: [2751840,6089832]
16758243290880: [2817360,5948208]

24959017348650: [2947050,8469153]
24959017348650: [2949705,8461530]
24959017348650: [4125870,6049395]
24959017348650: [4129587,6043950]
24959017348650: [4230765,5899410]

14593825548650: [returns no fangs]

Completed in  1.286374813709699 Seconds```

## Go

Translation of: C
`package main import (    "fmt"     "math" ) func max(a, b uint64) uint64 {    if a > b {        return a    }    return b} func min(a, b uint64) uint64 {    if a < b {        return a    }    return b } func ndigits(x uint64) (n int) {    for ; x > 0; x /= 10 {        n++     }    return } func dtally(x uint64) (t uint64) {    for ; x > 0; x /= 10 {        t += 1 << (x % 10 * 6)    }    return } var tens [20]uint64 func init() {    tens[0] = 1    for i := 1; i < 20; i++ {        tens[i] = tens[i-1] * 10    }} func fangs(x uint64) (f []uint64) {    nd := ndigits(x)    if nd&1 == 1 {        return    }    nd /= 2    lo := max(tens[nd-1], (x+tens[nd]-2)/(tens[nd]-1))    hi := min(x/lo, uint64(math.Sqrt(float64(x))))    t := dtally(x)    for a := lo; a <= hi; a++ {        b := x / a        if a*b == x &&            (a%10 > 0 || b%10 > 0) &&            t == dtally(a)+dtally(b) {            f = append(f, a)        }    }    return} func showFangs(x uint64, f []uint64) {    fmt.Print(x)    if len(f) > 1 {        fmt.Println()    }    for _, a := range f {        fmt.Println(" =", a, "×", x/a)    }} func main() {    for x, n := uint64(1), 0; n < 26; x++ {        if f := fangs(x); len(f) > 0 {            n++            fmt.Printf("%2d: ", n)            showFangs(x, f)        }    }    fmt.Println()    for _, x := range []uint64{16758243290880, 24959017348650, 14593825548650} {        if f := fangs(x); len(f) > 0 {            showFangs(x, f)        } else {            fmt.Println(x, "is not vampiric")        }    }}`
Output:
``` 1: 1260 = 21 × 60
2: 1395 = 15 × 93
3: 1435 = 35 × 41
4: 1530 = 30 × 51
5: 1827 = 21 × 87
6: 2187 = 27 × 81
7: 6880 = 80 × 86
8: 102510 = 201 × 510
9: 104260 = 260 × 401
10: 105210 = 210 × 501
11: 105264 = 204 × 516
12: 105750 = 150 × 705
13: 108135 = 135 × 801
14: 110758 = 158 × 701
15: 115672 = 152 × 761
16: 116725 = 161 × 725
17: 117067 = 167 × 701
18: 118440 = 141 × 840
19: 120600 = 201 × 600
20: 123354 = 231 × 534
21: 124483 = 281 × 443
22: 125248 = 152 × 824
23: 125433 = 231 × 543
24: 125460
= 204 × 615
= 246 × 510
25: 125500 = 251 × 500
26: 126027 = 201 × 627

16758243290880
= 1982736 × 8452080
= 2123856 × 7890480
= 2751840 × 6089832
= 2817360 × 5948208
24959017348650
= 2947050 × 8469153
= 2949705 × 8461530
= 4125870 × 6049395
= 4129587 × 6043950
= 4230765 × 5899410
14593825548650 is not vampiric
```

`import Data.List (sort)import Control.Arrow ((&&&)) -- VAMPIRE NUMBERS ------------------------------------------------------------vampires :: [Int]vampires = filter (not . null . fangs) [1 ..] fangs :: Int -> [(Int, Int)]fangs n  | odd w = []  | otherwise = ((,) <*> quot n) <\$> filter isfang (integerFactors n)  where    ndigit :: Int -> Int    ndigit 0 = 0    ndigit n = 1 + ndigit (quot n 10)    w = ndigit n    xmin = 10 ^ (quot w 2 - 1)    xmax = xmin * 10    isfang x =      x > xmin &&      x < y &&      y < xmax && -- same length      (quot x 10 /= 0 || quot y 10 /= 0) && -- not zero-ended      sort (show n) == sort (show x ++ show y)      where        y = quot n x -- FACTORS --------------------------------------------------------------------integerFactors :: Int -> [Int]integerFactors n  | n < 1 = []  | otherwise =    lows ++    (quot n <\$>     (if intSquared == n -- A perfect square,        then tail -- and cofactor of square root would be redundant.        else id)       (reverse lows))  where    (intSquared, lows) =      (^ 2) &&& (filter ((0 ==) . rem n) . enumFromTo 1) \$      floor (sqrt \$ fromIntegral n) -- TEST -----------------------------------------------------------------------main :: IO [()]main =  mapM    (print . ((,) <*>) fangs)    (take 25 vampires ++ [16758243290880, 24959017348650, 14593825548650])`
Output:
```(1260,[(21,60)])
(1395,[(15,93)])
(1435,[(35,41)])
(1530,[(30,51)])
(1827,[(21,87)])
(2187,[(27,81)])
(6880,[(80,86)])
(102510,[(201,510)])
(104260,[(260,401)])
(105210,[(210,501)])
(105264,[(204,516)])
(105750,[(150,705)])
(108135,[(135,801)])
(110758,[(158,701)])
(115672,[(152,761)])
(116725,[(161,725)])
(117067,[(167,701)])
(118440,[(141,840)])
(120600,[(201,600)])
(123354,[(231,534)])
(124483,[(281,443)])
(125248,[(152,824)])
(125433,[(231,543)])
(125460,[(204,615),(246,510)])
(125500,[(251,500)])
(16758243290880,[(1982736,8452080),(2123856,7890480),(2751840,6089832),(2817360,5948208)])
(24959017348650,[(2947050,8469153),(2949705,8461530),(4125870,6049395),(4129587,6043950),(4230765,5899410)])
(14593825548650,[])```

## Icon and Unicon

The following works in both languages.

`procedure main()    write("First 25 vampire numbers and their fangs:")    every fangs := vampire(n := seq())\25 do write(right(n,20),":",fangs)    write("\nOther numbers:")    every n := 16758243290880 | 24959017348650 | 14593825548650 do        write(right(n,20),": ",vampire(n)|"toothless")end procedure vampire(n)    ns := string(n)    if *ns % 2 = 1 then fail    every (fangs := "") ||:= " "||fangCheck(n, *ns/2, f1 := 2 to integer(sqrt(n)), n/f1)    if *fangs > 0 then return fangsend procedure fangCheck(n, n2, f1, f2)    if f1*f2 ~= n then fail    if n2 ~= *(f1|f2) then fail    if (f1|f2) % 10 ~= 0 then         if csort(f1||f2) == csort(n) then return "("||f1||","||f2||")"end procedure csort(s)  # Adapted from csort(s) in Icon IPL    every (s1 := "", c := !cset(s)) do every find(c, s) do s1 ||:= c    return s1end`

Output:

```First 25 vampire numbers and their fangs:
1260: (21,60)
1395: (15,93)
1435: (35,41)
1530: (30,51)
1827: (21,87)
2187: (27,81)
6880: (80,86)
102510: (201,510)
104260: (260,401)
105210: (210,501)
105264: (204,516)
105750: (150,705)
108135: (135,801)
110758: (158,701)
115672: (152,761)
116725: (161,725)
117067: (167,701)
118440: (141,840)
120600: (201,600)
123354: (231,534)
124483: (281,443)
125248: (152,824)
125433: (231,543)
125460: (204,615) (246,510)
125500: (251,500)

Other numbers:
16758243290880: (1982736,8452080) (2123856,7890480) (2751840,6089832) (2817360,5948208)
24959017348650: (2947050,8469153) (2949705,8461530) (4125870,6049395) (4129587,6043950) (4230765,5899410)
14593825548650: toothless
```

## J

` Filter=: (#~`)(`:6)odd =: 2&|even =: [email protected]:oddfactors =: [: ([: /:~ [: */"1 ([: x: [) ^"1 [: > [: , [: { [: <@:[email protected]>: ])/ __ q: ]digits =: 10&(#.inv)tally =: # : [:half =: -: : [:even_number_of_digits =: [email protected]:[email protected]:digitssame_digits =: [email protected]:[ -:&(/:~) ,&digits/@:]assert 1 -: 1234 same_digits 23 14assert 0 -: 1234 same_digits 23 140half_the_digits =: ([email protected]:[email protected]:[email protected]:[ = [email protected]:digits&>@:]) # ]factors_with_half_the_digits =: half_the_digits factorslarge =: (> <[email protected]:%:)~ # ]candidates =: large factors_with_half_the_digitsone_trailing_zero_permitted =: (0 < [: tally 0 -.~ 10&|)"1 Filterpairs =: (% ,. ]) [email protected]:candidatesfangs =: (same_digits"0 1 # ]) pairs    A=:(0 2 [email protected]:-: \$)&>Filter<@fangs"0]1000+i.1e4   B=:(0 2 [email protected]:-: \$)&>Filter<@fangs"0]100000+i.25501   (,: */@:{.&.>)A,B┌─────┬─────┬─────┬─────┬─────┬─────┬─────┬───────┬───────┬───────┬───────┬───────┬───────┬───────┬───────┬───────┬───────┬───────┬───────┬───────┬───────┬───────┬───────┬───────┬───────┐│21 60│15 93│35 41│30 51│21 87│27 81│80 86│201 510│260 401│210 501│204 516│150 705│135 801│158 701│152 761│161 725│167 701│141 840│201 600│231 534│281 443│152 824│231 543│246 510│251 500││     │     │     │     │     │     │     │       │       │       │       │       │       │       │       │       │       │       │       │       │       │       │       │204 615│       │├─────┼─────┼─────┼─────┼─────┼─────┼─────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┤│1260 │1395 │1435 │1530 │1827 │2187 │6880 │102510 │104260 │105210 │105264 │105750 │108135 │110758 │115672 │116725 │117067 │118440 │120600 │123354 │124483 │125248 │125433 │125460 │125500 │└─────┴─────┴─────┴─────┴─────┴─────┴─────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┘    <@fangs"0[] 16758243290880 24959017348650 14593825548650┌───────────────┬───────────────┬──┐│2817360 5948208│4230765 5899410│  ││2751840 6089832│4129587 6043950│  ││2123856 7890480│4125870 6049395│  ││1982736 8452080│2949705 8461530│  ││               │2947050 8469153│  │└───────────────┴───────────────┴──┘    fangs f.  NB. <laugh>((10&(#.^:_1)@:[ -:&(/:~) ,&(10&(#.^:_1))/@:])"0 1 # ]) ((% ,. ]) (#~ (0 < [: # :[: 0 -.~ 10&|)"1)@:(((> <[email protected]:%:)~ # ]) (((-: :[:@:(# :[:)@:(10&(#.^:_1))@:[ = # :[:@:(10&(#.^:_1))&>@:]) # ]) ([: ([: /:~ [: */"1 ([: x: [) ^"1 [: > [: , [: { [: <@:[email protected]>: ])/ __ q: ])))) `

## Java

Works with: Java version 1.5+
`import java.util.Arrays;import java.util.HashSet; public class VampireNumbers{    private static int numDigits(long num){        return Long.toString(Math.abs(num)).length();    }     private static boolean fangCheck(long orig, long fang1, long fang2){        if(Long.toString(fang1).endsWith("0") && Long.toString(fang2).endsWith("0")) return false;         int origLen = numDigits(orig);        if(numDigits(fang1) != origLen / 2 || numDigits(fang2) != origLen / 2) return false;         byte[] origBytes = Long.toString(orig).getBytes();        byte[] fangBytes = (Long.toString(fang1) + Long.toString(fang2)).getBytes();        Arrays.sort(origBytes);        Arrays.sort(fangBytes);        return Arrays.equals(origBytes, fangBytes);    }     public static void main(String[] args){        HashSet<Long> vamps = new HashSet<Long>();        for(long i = 10; vamps.size() <= 25; i++ ){            if((numDigits(i) % 2) != 0) {i = i * 10 - 1; continue;}            for(long fang1 = 2; fang1 <= Math.sqrt(i) + 1; fang1++){                if(i % fang1 == 0){                    long fang2 = i / fang1;                    if(fangCheck(i, fang1, fang2) && fang1 <= fang2){                        vamps.add(i);                        System.out.println(i + ": [" + fang1 + ", " + fang2 +"]");                    }                }            }        }        Long[] nums = {16758243290880L, 24959017348650L, 14593825548650L};        for(Long i : nums){            for(long fang1 = 2; fang1 <= Math.sqrt(i) + 1; fang1++){                if(i % fang1 == 0){                    long fang2 = i / fang1;                    if(fangCheck(i, fang1, fang2) && fang1 <= fang2){                        System.out.println(i + ": [" + fang1 + ", " + fang2 +"]");                    }                }            }        }    }}`

Output:

```1260: [21, 60]
1395: [15, 93]
1435: [35, 41]
1530: [30, 51]
1827: [21, 87]
2187: [27, 81]
6880: [80, 86]
102510: [201, 510]
104260: [260, 401]
105210: [210, 501]
105264: [204, 516]
105750: [150, 705]
108135: [135, 801]
110758: [158, 701]
115672: [152, 761]
116725: [161, 725]
117067: [167, 701]
118440: [141, 840]
120600: [201, 600]
123354: [231, 534]
124483: [281, 443]
125248: [152, 824]
125433: [231, 543]
125460: [204, 615]
125460: [246, 510]
125500: [251, 500]
126027: [201, 627]
16758243290880: [1982736, 8452080]
16758243290880: [2123856, 7890480]
16758243290880: [2751840, 6089832]
16758243290880: [2817360, 5948208]
24959017348650: [2947050, 8469153]
24959017348650: [2949705, 8461530]
24959017348650: [4125870, 6049395]
24959017348650: [4129587, 6043950]
24959017348650: [4230765, 5899410]```

### Alternative version

`public class VampireNumber {     public static void main(String args[]) {         // scan only the ranges that have an even number of digits        // for instance: 10 .. 99, 1000 .. 9999 etc        long countVamps = 0, start = 10, tens = 10;        outer:        for (int numDigits = 2; numDigits <= 18; numDigits += 2) {            long end = start * 10;            for (long i = start; i < end; i++) {                if (countFangs(i, tens) > 0) {                    if (++countVamps >= 26)                        break outer;                }            }            start *= 100;            tens *= 10;        }        System.out.println();         long[] bigs = {16758243290880L, 24959017348650L,            14593825548650L};         for (long b : bigs)            countFangs(b, 10000000L);    }     private static int countFangs(long n, long tens) {        int countFangs = 0;         // limit the search space for factors (as in C example)        long lo = Math.max(tens / 10, (n + tens - 2) / (tens - 1));        long hi = Math.min(n / lo, (long) Math.sqrt(n));         long nTally = tallyDigits(n);         for (long a = lo; a <= hi; a++) {            long b = n / a;             if (a * b != n)                continue;             // check for mod 9 congruence            if (n % 9 != (a + b) % 9)                continue;             if (a % 10 == 0 && b % 10 == 0)                continue;             if (nTally == tallyDigits(a) + tallyDigits(b)) {                if (countFangs == 0)                    System.out.printf("\n%d : ", n);                System.out.printf("[%d, %d]", a, b);                countFangs++;            }        }        return countFangs;    }     // sum to a unique number to represent set of digits (as in C example)    private static long tallyDigits(long n) {        long total = 0;        while (n > 0) {            total += 1L << ((n % 10) * 6);            n /= 10;        }        return total;    }}`

Output:

```1260 : [21, 60]
1395 : [15, 93]
1435 : [35, 41]
1530 : [30, 51]
1827 : [21, 87]
2187 : [27, 81]
6880 : [80, 86]
102510 : [201, 510]
104260 : [260, 401]
105210 : [210, 501]
105264 : [204, 516]
105750 : [150, 705]
108135 : [135, 801]
110758 : [158, 701]
115672 : [152, 761]
116725 : [161, 725]
117067 : [167, 701]
118440 : [141, 840]
120600 : [201, 600]
123354 : [231, 534]
124483 : [281, 443]
125248 : [152, 824]
125433 : [231, 543]
125460 : [204, 615][246, 510]
125500 : [251, 500]
126027 : [201, 627]

16758243290880 : [1982736, 8452080][2123856, 7890480][2751840, 6089832][2817360, 5948208]
24959017348650 : [2947050, 8469153][2949705, 8461530][4125870, 6049395][4129587, 6043950][4230765, 5899410]```

## Julia

Functions

` function divisors{T<:Integer}(n::T)    !isprime(n) || return [one(T), n]    d = [one(T)]    for (k, v) in factor(n)        e = T[k^i for i in 1:v]        append!(d, vec([i*j for i in d, j in e]))    end    sort(d)end function vampirefangs{T<:Integer}(n::T)    fangs = T[]    isvampire = false    vdcnt = ndigits(n)    fdcnt = vdcnt>>1    iseven(vdcnt) || return (isvampire, fangs)    !isprime(n) || return (isvampire, fangs)    vdigs = sort(digits(n))    d = divisors(n)    len = length(d)    len = iseven(len) ? len>>1 : len>>1 + 1    for f in d[1:len]        ndigits(f) == fdcnt || continue        g = div(n, f)        f%10!=0 || g%10!=0 || continue        sort([digits(f), digits(g)]) == vdigs || continue        isvampire = true        append!(fangs, [f, g])    end    if isvampire        fangs = reshape(fangs, (2,length(fangs)>>1))'    end    return (isvampire, fangs)end `

Main

` function showvampire{T<:Integer}(i::T, n::T, fangs::Array{T,2})    s = @sprintf "%6d  %14d %s\n" i n join(fangs[1,:], "\u00d7")    for i in 2:size(fangs)[1]        s *= " "^23*join(fangs[i,:], "\u00d7")*"\n"    end    return send vgoal = 25vcnt = 0dcnt = 0println("Finding the first ", vgoal, " vampire numbers.")println("     N         Vampire Fangs")while vcnt < vgoal    dcnt += 2    for i in (10^(dcnt-1)):(10^dcnt-1)        (isvampire, fangs) = vampirefangs(i)        isvampire || continue        vcnt += 1        print(showvampire(vcnt, i, fangs))        vcnt < vgoal || break    endend test = [16758243290880, 24959017348650, 14593825548650]println()println("Checking a few numbers.")println("     N         Vampire Fangs")for (i, v) in enumerate(test)    (isvampire, fangs) = vampirefangs(v)    if isvampire        print(showvampire(i, v, fangs))    else        println(@sprintf "%6d  %14d is not a vampire" i v)    endend `
Output:
```Finding the first 25 vampire numbers.
N         Vampire Fangs
1            1260 21×60
2            1395 15×93
3            1435 35×41
4            1530 30×51
5            1827 21×87
6            2187 27×81
7            6880 80×86
8          102510 201×510
9          104260 260×401
10          105210 210×501
11          105264 204×516
12          105750 150×705
13          108135 135×801
14          110758 158×701
15          115672 152×761
16          116725 161×725
17          117067 167×701
18          118440 141×840
19          120600 201×600
20          123354 231×534
21          124483 281×443
22          125248 152×824
23          125433 231×543
24          125460 204×615
246×510
25          125500 251×500

Checking a few numbers.
N         Vampire Fangs
1  16758243290880 1982736×8452080
2123856×7890480
2751840×6089832
2817360×5948208
2  24959017348650 2947050×8469153
2949705×8461530
4125870×6049395
4129587×6043950
4230765×5899410
3  14593825548650 is not a vampire
```

## Kotlin

`// version 1.1 data class Fangs(val fang1: Long = 0L, val fang2: Long = 0L) fun pow10(n: Int): Long = when {    n < 0 -> throw IllegalArgumentException("Can't be negative")    else -> {        var pow = 1L        for (i in 1..n) pow *= 10L        pow    }} fun countDigits(n: Long): Int = when {    n < 0L -> throw IllegalArgumentException("Can't be negative")    n == 0L -> 1    else -> {        var count = 0        var nn = n        while (nn > 0L) {            count++            nn /= 10L        }        count    }} fun hasTrailingZero(n: Long): Boolean = when {    n < 0L -> throw IllegalArgumentException("Can't be negative")    else -> n % 10L == 0L} fun sortedString(s: String): String {    val ca = s.toCharArray()    ca.sort()    return String(ca)} fun isVampiric(n: Long, fl: MutableList<Fangs>): Boolean {    if (n < 0L) return false    val len = countDigits(n)    if (len % 2L == 1L) return false    val hlen = len / 2    val first = pow10(hlen - 1)    val last = 10L * first    var j: Long    var cd: Int    val ss = sortedString(n.toString())    for (i in first until last) {        if (n % i != 0L) continue        j = n / i        if (j < i) return fl.size > 0        cd = countDigits(j)        if (cd > hlen) continue        if (cd < hlen) return fl.size > 0        if (ss != sortedString(i.toString() + j.toString())) continue        if (!(hasTrailingZero(i) && hasTrailingZero(j))) {            fl.add(Fangs(i, j))        }    }    return fl.size > 0} fun showFangs(fangsList: MutableList<Fangs>): String {    var s = ""    for ((fang1, fang2) in fangsList) {        s += " = \$fang1 x \$fang2"    }    return s} fun main(args: Array<String>) {    println("The first 25 vampire numbers and their fangs are:")    var count = 0    var n: Long = 0    val fl = mutableListOf<Fangs>()    while (true) {        if (isVampiric(n, fl)) {            count++            println("\${"%2d".format(count)} : \$n\t\${showFangs(fl)}")            fl.clear()            if (count == 25) break        }        n++    }    println()    val va = longArrayOf(16758243290880L, 24959017348650L, 14593825548650L)    for (v in va) {        if (isVampiric(v, fl)) {            println("\$v\t\${showFangs(fl)}")            fl.clear()        } else {            println("\$v\t = not vampiric")        }    }}`
Output:
```The first 25 vampire numbers and their fangs are:
1 : 1260        = 21 x 60
2 : 1395        = 15 x 93
3 : 1435        = 35 x 41
4 : 1530        = 30 x 51
5 : 1827        = 21 x 87
6 : 2187        = 27 x 81
7 : 6880        = 80 x 86
8 : 102510      = 201 x 510
9 : 104260      = 260 x 401
10 : 105210      = 210 x 501
11 : 105264      = 204 x 516
12 : 105750      = 150 x 705
13 : 108135      = 135 x 801
14 : 110758      = 158 x 701
15 : 115672      = 152 x 761
16 : 116725      = 161 x 725
17 : 117067      = 167 x 701
18 : 118440      = 141 x 840
19 : 120600      = 201 x 600
20 : 123354      = 231 x 534
21 : 124483      = 281 x 443
22 : 125248      = 152 x 824
23 : 125433      = 231 x 543
24 : 125460      = 204 x 615 = 246 x 510
25 : 125500      = 251 x 500

16758243290880   = 1982736 x 8452080 = 2123856 x 7890480 = 2751840 x 6089832 = 2817360 x 5948208
24959017348650   = 2947050 x 8469153 = 2949705 x 8461530 = 4125870 x 6049395 = 4129587 x 6043950 = 4230765 x 5899410
14593825548650   = not vampiric
```

## Mathematica

`ClearAll[VampireQ]VampireQ[num_Integer] := Module[{poss, divs},  divs = Select[Divisors[num], # <= Sqrt[num] &];  poss = {#, num/#} & /@ divs;  If[Length[poss] > 0,   poss = Select[poss, Mod[#, 10] =!= {0, 0} &];   If[Length[poss] > 0,    poss = Select[poss, Length[IntegerDigits[First[#]]] == Length[IntegerDigits[Last[#]]] &];    If[Length[poss] > 0,     poss = Select[poss, Sort[IntegerDigits[num]] == Sort[Join @@ (IntegerDigits /@ #)] &];     If[Length[poss] > 0      ,      Sow[{num, poss}];      True      ,      False     ]    ,    False    ]   ,   False   ]  ,  False ]]`

Testing out the function:

`Reap[Scan[VampireQ,Range[126027]]][[2,1]]//GridReap[VampireQ[#]] & /@ {16758243290880, 24959017348650, 14593825548650} // Grid`
Output:
```1260	{{21,60}}
1395	{{15,93}}
1435	{{35,41}}
1530	{{30,51}}
1827	{{21,87}}
2187	{{27,81}}
6880	{{80,86}}
102510	{{201,510}}
104260	{{260,401}}
105210	{{210,501}}
105264	{{204,516}}
105750	{{150,705}}
108135	{{135,801}}
110758	{{158,701}}
115672	{{152,761}}
116725	{{161,725}}
117067	{{167,701}}
118440	{{141,840}}
120600	{{201,600}}
123354	{{231,534}}
124483	{{281,443}}
125248	{{152,824}}
125433	{{231,543}}
125460	{{204,615},{246,510}}
125500	{{251,500}}

True	{{{16758243290880,{{1982736,8452080},{2123856,7890480},{2751840,6089832},{2817360,5948208}}}}}
True	{{{24959017348650,{{2947050,8469153},{2949705,8461530},{4125870,6049395},{4129587,6043950},{4230765,5899410}}}}}
False	{}```

## PARI/GP

 Some lines in this example are too long (more than 80 characters). Please fix the code if it's possible and remove this message.
`fang(n)=my(v=digits(n),u=List());if(#v%2,return([]));fordiv(n,d,if(#Str(d)==#v/2 && #Str(n/d)==#v/2 && vecsort(v)==vecsort(concat(digits(d),digits(n/d))) && (d%10 || (n/d)%10), if(d^2>n,return(Vec(u))); listput(u, d))); Vec(u)k=25;forstep(d=4,6,2,for(n=10^(d-1),10^d-1,f=fang(n); for(i=1,#f,print(n" "f[i]" "n/f[i]); if(i==#f && k--==0,return))))print();v=[16758243290880, 24959017348650, 14593825548650];for(i=1,#v,f=fang(v[i]); for(j=1,#f, print(v[i]" "f[j]" "v[i]/f[j])))`

Output:

```1260 21 60
1395 15 93
1435 35 41
1530 30 51
1827 21 87
2187 27 81
6880 80 86
102510 201 510
104260 260 401
105210 210 501
105264 204 516
105750 150 705
108135 135 801
110758 158 701
115672 152 761
116725 161 725
117067 167 701
118440 141 840
120600 201 600
123354 231 534
124483 281 443
125248 152 824
125433 231 543
125460 204 615
125460 246 510
125500 251 500

16758243290880 1982736 8452080
16758243290880 2123856 7890480
16758243290880 2751840 6089832
16758243290880 2817360 5948208
24959017348650 2947050 8469153
24959017348650 2949705 8461530
24959017348650 4125870 6049395
24959017348650 4129587 6043950
24959017348650 4230765 5899410```

## Perl

The trailing zeros condition is first triggered when searching for the 26th vampire number.

`#!/usr/bin/perluse warnings;use strict;use feature qw(say); sub fangs {    my \$vampire = shift;    my \$length  = length 0 + \$vampire;    return if \$length % 2;    my \$fang_length = \$length / 2;    my \$from        = '1' . '0' x (\$fang_length - 1);    my \$to          = '9' x \$fang_length;    my \$sorted      = join q(), sort split //, \$vampire;    my @fangs;    for my \$f1 (\$from .. 1 + sqrt \$vampire) {        next if \$vampire % \$f1;        my \$f2 = \$vampire / \$f1;        next if \$sorted ne join q(), sort split //, \$f1 . \$f2;        next if 2 == grep '0' eq substr(\$_, -1 , 1), \$f1, \$f2; # Needed for the 26th number.        push @fangs, [\$f1, \$f2];    }    return @fangs;} my \$count = 0;my \$i     = 9;while (\$count < 25) {    \$i++;    my @f = fangs(\$i);    \$count++, say join ' ', "\$count. \$i:", map "[@\$_]", @f if @f;} say join ' ', \$_, map "[@\$_]", fangs(\$_) for 16758243290880, 24959017348650, 14593825548650;`

A faster version, using the `divisors()` function from the `ntheory` library.

Translation of: Sidef
Library: ntheory
`use ntheory qw(sqrtint logint divisors); sub is_vampire {    my (\$n) = @_;     return if (length(\$n) % 2 or \$n < 0);     my \$l1 = 10**logint(sqrtint(\$n), 10);    my \$l2 = sqrtint(\$n);     my \$s = join('', sort split(//, \$n));     my @fangs;     foreach my \$d (divisors(\$n)) {         \$d < \$l1 and next;        \$d > \$l2 and last;         my \$t = \$n / \$d;         next if (\$d % 10 == 0 and \$t % 10 == 0);        next if (join('', sort split(//, "\$d\$t")) ne \$s);         push @fangs, [\$d, \$t];    }     return @fangs;} print "First 25 Vampire Numbers:\n"; for (my (\$n, \$i) = (1, 1) ; \$i <= 25 ; ++\$n) {    if (my @fangs = is_vampire(\$n)) {        printf("%2d. %6s : %s\n", \$i++, \$n, join(' ', map { "[@\$_]" } @fangs));    }} print "\nIndividual tests:\n"; foreach my \$n (16758243290880, 24959017348650, 14593825548650) {    my @fangs = is_vampire(\$n);    print("\$n: ", (@fangs ? join(' ', map { "[@\$_]" } @fangs)                          : "is not a vampire number"), "\n");}`
Output:
```First 25 Vampire Numbers:
1.   1260 : [21 60]
2.   1395 : [15 93]
3.   1435 : [35 41]
4.   1530 : [30 51]
5.   1827 : [21 87]
6.   2187 : [27 81]
7.   6880 : [80 86]
8. 102510 : [201 510]
9. 104260 : [260 401]
10. 105210 : [210 501]
11. 105264 : [204 516]
12. 105750 : [150 705]
13. 108135 : [135 801]
14. 110758 : [158 701]
15. 115672 : [152 761]
16. 116725 : [161 725]
17. 117067 : [167 701]
18. 118440 : [141 840]
19. 120600 : [201 600]
20. 123354 : [231 534]
21. 124483 : [281 443]
22. 125248 : [152 824]
23. 125433 : [231 543]
24. 125460 : [204 615] [246 510]
25. 125500 : [251 500]

Individual tests:
16758243290880: [1982736 8452080] [2123856 7890480] [2751840 6089832] [2817360 5948208]
24959017348650: [2947050 8469153] [2949705 8461530] [4125870 6049395] [4129587 6043950] [4230765 5899410]
14593825548650: is not a vampire number
```

## Perl 6

`sub is_vampire (Int \$num) {    my \$digits = \$num.comb.sort;    my @fangs;    (10**\$num.sqrt.log(10).floor .. \$num.sqrt.ceiling).map: -> \$this {        next if \$num % \$this;        my \$that = \$num div \$this;        next if \$this %% 10 && \$that %% 10;        @fangs.push("\$this x \$that") if (\$this ~ \$that).comb.sort eq \$digits;    }    @fangs} constant @vampires = flat (3..*).map: -> \$s, \$e {    (10**\$s .. 10**\$e).hyper.map: -> \$n {        next unless my @fangs = is_vampire(\$n);        "\$n: { @fangs.join(', ') }"    }} say "\nFirst 25 Vampire Numbers:\n"; .say for @vampires[^25]; say "\nIndividual tests:\n"; .say for (16758243290880, 24959017348650, 14593825548650).hyper(:1batch).map: {    "\$_: " ~ (is_vampire(\$_).join(', ') || 'is not a vampire number.')}`
```First 25 Vampire Numbers:

1260: 21 x 60
1395: 15 x 93
1435: 35 x 41
1530: 30 x 51
1827: 21 x 87
2187: 27 x 81
6880: 80 x 86
102510: 201 x 510
104260: 260 x 401
105210: 210 x 501
105264: 204 x 516
105750: 150 x 705
108135: 135 x 801
110758: 158 x 701
115672: 152 x 761
116725: 161 x 725
117067: 167 x 701
118440: 141 x 840
120600: 201 x 600
123354: 231 x 534
124483: 281 x 443
125248: 152 x 824
125433: 231 x 543
125460: 204 x 615, 246 x 510
125500: 251 x 500

Individual tests:

16758243290880: 1982736 x 8452080, 2123856 x 7890480, 2751840 x 6089832, 2817360 x 5948208
24959017348650: 2947050 x 8469153, 2949705 x 8461530, 4125870 x 6049395, 4129587 x 6043950, 4230765 x 5899410
14593825548650: is not a vampire number.```

## Phix

`function vampire(atom v)    sequence res = {}    if v>=0 then        string vs = sprintf("%d",v)        if mod(length(vs),2)=0 then -- even length            vs = sort(vs)            for i=power(10,length(vs)/2-1) to floor(sqrt(v)) do                if remainder(v,i)=0 then                    integer i2 = v/i                    string si = sprintf("%d",i),                           s2 = sprintf("%d",i2)                    if (si[\$]!='0' or s2[\$]!='0')                    and sort(si&s2)=vs then                        res = append(res,{i,i2})                    end if                end if            end for        end if    end if    return resend function integer found = 0atom i = 0sequence resputs(1,"The first 26 vampire numbers and their fangs:\n")while found<26 do    res = vampire(i)    if length(res) then        found += 1        printf(1,"%d: %d: %s\n",{found,i,sprint(res)})    end if    i += 1end whileputs(1,"\n") constant tests = {16758243290880,                  24959017348650,                  14593825548650} for t=1 to length(tests) do    i = tests[t]    res = vampire(i)    printf(1,"%d: %s\n",{i,iff(res={}?"not a vampire number":sprint(res))})end for`
Output:
```The first 26 vampire numbers and their fangs:
1: 1260: {{21,60}}
2: 1395: {{15,93}}
3: 1435: {{35,41}}
4: 1530: {{30,51}}
5: 1827: {{21,87}}
6: 2187: {{27,81}}
7: 6880: {{80,86}}
8: 102510: {{201,510}}
9: 104260: {{260,401}}
10: 105210: {{210,501}}
11: 105264: {{204,516}}
12: 105750: {{150,705}}
13: 108135: {{135,801}}
14: 110758: {{158,701}}
15: 115672: {{152,761}}
16: 116725: {{161,725}}
17: 117067: {{167,701}}
18: 118440: {{141,840}}
19: 120600: {{201,600}}
20: 123354: {{231,534}}
21: 124483: {{281,443}}
22: 125248: {{152,824}}
23: 125433: {{231,543}}
24: 125460: {{204,615},{246,510}}
25: 125500: {{251,500}}
26: 126027: {{201,627}}

16758243290880: {{1982736,8452080},{2123856,7890480},{2751840,6089832},{2817360,5948208}}
24959017348650: {{2947050,8469153},{2949705,8461530},{4125870,6049395},{4129587,6043950},{4230765,5899410}}
14593825548650: not a vampire number
```

## PureBasic

`EnableExplicitDisableDebugger Macro CheckVamp(CheckNum)  c=0 : i=CheckNum : Print(~"\nCheck number: "+Str(i)+~"\n")  Gosub VampireLoop : If c=0 : Print(Str(i)+" is not vampiric.") : EndIf : PrintN("")EndMacro Procedure.i Factor(number.i,counter.i)  If number>0 And number>=counter*counter And number%counter=0      ProcedureReturn counter  EndIf    ProcedureReturn 0EndProcedure Procedure.b IsVampire(f1.i,f2.i)  Define a.s=Str(f1*f2),         b.s=Str(f1),         c.s=Str(f2),         d.s=b+c,         i.i  If Len(a)=Len(d) And Len(b)=Len(c)    While Len(a)      i=FindString(d,Left(a,1))      If i        a=Mid(a,2)        d=RemoveString(d,Mid(d,i,1),#PB_String_NoCase,i,1)      Else        ProcedureReturn #False              EndIf    Wend    ProcedureReturn Bool(Len(d)=0)  EndIf  ProcedureReturn #FalseEndProcedure OpenConsole("Vampire number")Define i.i,       j.i,       m.i,       c.i=0 PrintN("The first 25 Vampire numbers...")While c<25 : i+1 : Gosub VampireLoop : WendPrintN("")CheckVamp(16758243290880) : CheckVamp(24959017348650) : CheckVamp(14593825548650)Input()End VampireLoop:  For j=1 To Int(Sqr(i))    If Factor(i,j)>0      m=i/j    Else      Continue    EndIf    If IsVampire(m,j)      c+1      PrintN(RSet(Str(c),3," ")+". "+RSet(Str(i),10," ")+": ["+Str(j)+", "+Str(m)+"]")    EndIf      Next  Return`
Output:
```The first 25 Vampire numbers...
1.       1260: [21, 60]
2.       1395: [15, 93]
3.       1435: [35, 41]
4.       1530: [30, 51]
5.       1827: [21, 87]
6.       2187: [27, 81]
7.       6880: [80, 86]
8.     102510: [201, 510]
9.     104260: [260, 401]
10.     105210: [210, 501]
11.     105264: [204, 516]
12.     105750: [150, 705]
13.     108135: [135, 801]
14.     110758: [158, 701]
15.     115672: [152, 761]
16.     116725: [161, 725]
17.     117067: [167, 701]
18.     118440: [141, 840]
19.     120600: [201, 600]
20.     123354: [231, 534]
21.     124483: [281, 443]
22.     125248: [152, 824]
23.     125433: [231, 543]
24.     125460: [204, 615]
25.     125460: [246, 510]

Check number: 16758243290880
1. 1675824329: [1982736, 8452080]
2. 1675824329: [2123856, 7890480]
3. 1675824329: [2751840, 6089832]
4. 1675824329: [2817360, 5948208]

Check number: 24959017348650
1. 2495901734: [2947050, 8469153]
2. 2495901734: [2949705, 8461530]
3. 2495901734: [4125870, 6049395]
4. 2495901734: [4129587, 6043950]
5. 2495901734: [4230765, 5899410]

Check number: 14593825548650
14593825548650 is not vampiric.```

## Python

This routine finds all the fangs for a number.

`from __future__ import division import mathfrom operator import mulfrom itertools import productfrom functools import reduce  def fac(n):    '''\    return the prime factors for n    >>> fac(600)    [5, 5, 3, 2, 2, 2]    >>> fac(1000)    [5, 5, 5, 2, 2, 2]    >>>      '''    step = lambda x: 1 + x*4 - (x//2)*2    maxq = int(math.floor(math.sqrt(n)))    d = 1    q = n % 2 == 0 and 2 or 3     while q <= maxq and n % q != 0:        q = step(d)        d += 1    res = []    if q <= maxq:        res.extend(fac(n//q))        res.extend(fac(q))     else: res=[n]    return res def fact(n):    '''\    return the prime factors and their multiplicities for n    >>> fact(600)    [(2, 3), (3, 1), (5, 2)]    >>> fact(1000)    [(2, 3), (5, 3)]    >>>     '''    res = fac(n)    return [(c, res.count(c)) for c in set(res)] def divisors(n):    'Returns all the divisors of n'    factors = fact(n)   # [(primefactor, multiplicity), ...]    primes, maxpowers = zip(*factors)    powerranges = (range(m+1) for m in maxpowers)    powers = product(*powerranges)    return (        reduce(mul,               (prime**power for prime, power in zip(primes, powergroup)),               1)        for powergroup in powers) def vampire(n):    fangsets = set( frozenset([d, n//d])                    for d in divisors(n)                    if (len(str(d)) == len(str(n))/2.                        and sorted(str(d) + str(n//d)) == sorted(str(n))                        and (str(d)[-1] == 0) + (str(n//d)[-1] == 0) <=1) )    return sorted(tuple(sorted(fangs)) for fangs in fangsets)  if __name__ == '__main__':    print('First 25 vampire numbers')    count = n = 0    while count <25:        n += 1        fangpairs = vampire(n)        if fangpairs:            count += 1            print('%i: %r' % (n, fangpairs))    print('\nSpecific checks for fangpairs')    for n in (16758243290880, 24959017348650, 14593825548650):        fangpairs = vampire(n)        print('%i: %r' % (n, fangpairs))`
Output:
```First 25 vampire numbers
1260: [(21, 60)]
1395: [(15, 93)]
1435: [(35, 41)]
1530: [(30, 51)]
1827: [(21, 87)]
2187: [(27, 81)]
6880: [(80, 86)]
102510: [(201, 510)]
104260: [(260, 401)]
105210: [(210, 501)]
105264: [(204, 516)]
105750: [(150, 705)]
108135: [(135, 801)]
110758: [(158, 701)]
115672: [(152, 761)]
116725: [(161, 725)]
117067: [(167, 701)]
118440: [(141, 840)]
120600: [(201, 600)]
123354: [(231, 534)]
124483: [(281, 443)]
125248: [(152, 824)]
125433: [(231, 543)]
125460: [(204, 615), (246, 510)]
125500: [(251, 500)]

Specific checks for fangpairs
16758243290880: [(1982736, 8452080), (2123856, 7890480), (2751840, 6089832), (2817360, 5948208)]
24959017348650: [(2947050, 8469153), (2949705, 8461530), (4125870, 6049395), (4129587, 6043950), (4230765, 5899410)]
14593825548650: []```

This alternative solution is not fast but it's short:

Translation of: Clojure
`from math import sqrtfrom itertools import imap, ifilter, islice, count def factor_pairs(n):    return ((x, n // x) for x in xrange(2, int(sqrt(n))) if n % x == 0) def fangs(n):    dlen = lambda x: len(str(x))    half = dlen(n) // 2    digits = lambda (x, y): sorted(str(x) + str(y))    halvesQ = lambda xs: all(y == half for y in imap(dlen, xs))    dn = sorted(str(n))    return [p for p in factor_pairs(n) if halvesQ(p) and dn==digits(p)] def vampiricQ(n):    fn = fangs(n)    return (n, fn) if fn else None for v in islice(ifilter(None, imap(vampiricQ, count())), 0, 25):    print v for n in [16758243290880, 24959017348650, 14593825548650]:    print vampiricQ(n) or str(n) + " is not vampiric."`
Output:
```(1260, [(21, 60)])
(1395, [(15, 93)])
(1435, [(35, 41)])
(1530, [(30, 51)])
(1827, [(21, 87)])
(2187, [(27, 81)])
(6880, [(80, 86)])
(102510, [(201, 510)])
(104260, [(260, 401)])
(105210, [(210, 501)])
(105264, [(204, 516)])
(105750, [(150, 705)])
(108135, [(135, 801)])
(110758, [(158, 701)])
(115672, [(152, 761)])
(116725, [(161, 725)])
(117067, [(167, 701)])
(118440, [(141, 840)])
(120600, [(201, 600)])
(123354, [(231, 534)])
(124483, [(281, 443)])
(125248, [(152, 824)])
(125433, [(231, 543)])
(125460, [(204, 615), (246, 510)])
(125500, [(251, 500)])
(16758243290880L, [(1982736, 8452080L), (2123856, 7890480L), (2751840, 6089832L), (2817360, 5948208L)])
(24959017348650L, [(2947050, 8469153L), (2949705, 8461530L), (4125870, 6049395L), (4129587, 6043950L), (4230765, 5899410L)])
14593825548650 is not vampiric.```

## Racket

Naive implementation, but notice the sequence-filter/sequence-map composition -- it's a good way to "find the first n numbers meeting predicate p?":

`#lang racket ;; chock full of fun... including divisors(require math/number-theory) ;; predicate to tell if n is a vampire number(define (sub-vampire?-and-fangs n)  (define digit-count-n (add1 (order-of-magnitude n)))  (define (string-sort-characters s) (sort (string->list s) char<?))  (define digits-in-order-n (string-sort-characters (number->string n)))  (define (fangs-of-n? d e)    (and (<= d e) ; avoid duplication         (= (add1 (order-of-magnitude d)) (add1 (order-of-magnitude e)) (/ digit-count-n 2))         (not (= 0 (modulo d 10) (modulo e 10)))         (equal? digits-in-order-n                 (string-sort-characters (string-append (number->string d) (number->string e))))))   (let* ((fangses (for*/list ((d (in-list (divisors n))) #:when (fangs-of-n? d (/ n d)))                    (list d (/ n d)))))    (and (not (null? fangses)) (cons n fangses)))) (define (vampire?-and-fangs n)  (and (odd? (order-of-magnitude n)) ; even number of digits - else not even worth looking!       (sub-vampire?-and-fangs n))) (displayln "First 25 vampire numbers:")(for ((vmp (sequence-filter identity (sequence-map vampire?-and-fangs (in-naturals 1))))      (cnt (in-range 1 (add1 25))))  (printf "#~a ~a~%" cnt vmp)) (displayln "Test the big numbers:")(displayln (vampire?-and-fangs 16758243290880))(displayln (vampire?-and-fangs 24959017348650))(displayln (vampire?-and-fangs 14593825548650))`

Output:

```First 25 vampire numbers:
#1 (1260 (21 60))
#2 (1395 (15 93))
#3 (1435 (35 41))
#4 (1530 (30 51))
#5 (1827 (21 87))
#6 (2187 (27 81))
#7 (6880 (80 86))
#8 (102510 (201 510))
#9 (104260 (260 401))
#10 (105210 (210 501))
#11 (105264 (204 516))
#12 (105750 (150 705))
#13 (108135 (135 801))
#14 (110758 (158 701))
#15 (115672 (152 761))
#16 (116725 (161 725))
#17 (117067 (167 701))
#18 (118440 (141 840))
#19 (120600 (201 600))
#20 (123354 (231 534))
#21 (124483 (281 443))
#22 (125248 (152 824))
#23 (125433 (231 543))
#24 (125460 (204 615) (246 510))
#25 (125500 (251 500))
Test the big numbers:
(16758243290880 (1982736 8452080) (2123856 7890480) (2751840 6089832) (2817360 5948208))
(24959017348650 (2947050 8469153) (2949705 8461530) (4125870 6049395) (4129587 6043950) (4230765 5899410))
#f```

## REXX

Note:   if the argument is negative, its absolute value is used to test if that single number is vampiric.

`/*REXX program displays  N  vampire numbers,  or  verifies  if  a number is vampiric.   */parse arg N .                                    /*obtain optional argument from the CL.*/if N=='' | N==","  then N= 25                    /*Not specified?  Then use the default.*/!.0= 1260;   !.1= 11453481;   !.2= 115672;   !.3= 124483;   !.4= 105264  /*lowest #, dig*/!.5= 1395;   !.6=   126846;   !.7=   1827;   !.8= 110758;   !.9= 156289  /*   "   "   " */#= 0;          L= length(N);       aN= abs(N)    /*num. of vampire numbers found, so far*/numeric digits max(9, length(aN) )               /*be able to handle ginormus numbers.  */@vamp= right('vampire number', 20)               /*literal used when showing a vampire #*/if N>0 then do j=1260  until  # >= N             /*search until N vampire numbers found.*/            if length(j) // 2  then do;  j= j*10 - 1;  iterate   /*bump J to even length*/                                    end                          /* [↑]  check if odd.  */            parse var  j  ''  -1  _              /*obtain the last decimal digit of  J. */            if j<!._  then iterate               /*is number tenable based on last dig? */            f= vampire(j)                        /*obtain the  fangs  of  J.            */            if f==''  then iterate               /*Are fangs null?   Yes, not vampire.  */            #= # + 1                             /*bump the vampire count, Vlad.        */            say @vamp   right(#, L)      "is: "      right(j, 9)',  fangs='   f            end   /*j*/                          /* [↑]  process a range of numbers.    */       else do;  f= vampire(aN)                  /* [↓]  process a number; obtain fangs.*/            if f==''  then say       aN     " isn't a vampire number."                      else say       aN     " is a vampire number, fangs="    f            endexit                                             /*stick a fork in it,  we're all done. *//*──────────────────────────────────────────────────────────────────────────────────────*/vampire: procedure; parse arg x,, \$. a bot;   L= length(x)  /*get arg;  compute len of X*/         if L//2  then return ''                            /*is L odd?   Then ¬vampire.*/                     do k=1  for L;    _= substr(x, k, 1);         \$._= \$._ || _                     end   /*k*/         w= L % 2                                           /*%:   is REXX's integer  ÷ */                     do m=0  for 10;   bot= bot || \$.m                     end   /*m*/         top= left( reverse(bot), w)         bot= left(bot, w)                                  /*determine limits of search*/         inc= x // 2    +    1                              /*X is odd? INC=2. No? INC=1*/         beg= max(bot, 10**(w-1) )                          /*calculate where  to start.*/         if inc==2  then  if  beg//2==0  then beg= beg + 1  /*possibly adjust the start.*/                                                            /* [↑]  odd  BEG  if odd INC*/                  do d=beg  to  min(top, 10**w - 1)  by inc /*use smart start, end, inc.*/                  if x // d \==0          then iterate      /*X  not ÷ by D?  Then skip,*/                  q= x % d;     if d>q    then iterate      /*is   D > Q      Then skip.*/                  if q*d//9 \== (q+d)//9  then iterate      /*modulo 9 congruence test. */                  if length(q)    \==w    then iterate      /*Len of Q ¬= W?  Then skip.*/                  parse var  q  ''  -1  _                   /*get last decimal dig. of Q*/                  if _==0                 then if right(d, 1) ==0  then iterate                  dq= d || q                  t= x;             do i=1  for  L;          p= pos( substr(dq, i, 1),  t)                                    if p==0  then iterate d; t= delstr(t, p, 1)                                    end   /*i*/                  a=a  '['d"∙"q'] '                         /*construct formatted fangs.*/                  end   /*d*/                               /* [↑]  ∙  is a round bullet*/         return a                                           /*return    formatted fangs.*/`
output   when using the default input:
```      vampire number  1 is:       1260,  fangs=  [21∙60]
vampire number  2 is:       1395,  fangs=  [15∙93]
vampire number  3 is:       1435,  fangs=  [35∙41]
vampire number  4 is:       1530,  fangs=  [30∙51]
vampire number  5 is:       1827,  fangs=  [21∙87]
vampire number  6 is:       2187,  fangs=  [27∙81]
vampire number  7 is:       6880,  fangs=  [80∙86]
vampire number  8 is:     102510,  fangs=  [201∙510]
vampire number  9 is:     104260,  fangs=  [260∙401]
vampire number 10 is:     105210,  fangs=  [210∙501]
vampire number 11 is:     105264,  fangs=  [204∙516]
vampire number 12 is:     105750,  fangs=  [150∙705]
vampire number 13 is:     108135,  fangs=  [135∙801]
vampire number 14 is:     110758,  fangs=  [158∙701]
vampire number 15 is:     115672,  fangs=  [152∙761]
vampire number 16 is:     116725,  fangs=  [161∙725]
vampire number 17 is:     117067,  fangs=  [167∙701]
vampire number 18 is:     118440,  fangs=  [141∙840]
vampire number 19 is:     120600,  fangs=  [201∙600]
vampire number 20 is:     123354,  fangs=  [231∙534]
vampire number 21 is:     124483,  fangs=  [281∙443]
vampire number 22 is:     125248,  fangs=  [152∙824]
vampire number 23 is:     125433,  fangs=  [231∙543]
vampire number 24 is:     125460,  fangs=  [204∙615]  [246∙510]
vampire number 25 is:     125500,  fangs=  [251∙500]
```
output   when using the input of:   -16758243290880
```16758243290880  is a vampire number, fangs=  [1982736∙8452080]  [2123856∙7890480]  [2751840∙6089832]  [2817360∙5948208]
```
output   when using the input of:   -24959017348650
```24959017348650  is a vampire number, fangs=  [2947050∙8469153]  [2949705∙8461530]  [4125870∙6049395]  [4129587∙6043950]  [4230765∙5899410]
```
output   when using the input of:   -14593825548650
```14593825548650  isn't a vampire number.
```

## Ring

` # Project : Vampire number for p = 10 to 127000     vampire(p)next func vampire(listnum)        sum = 0        flag = 1        list = list(len(string(listnum)))        total = newlist(len(list),2)       for n = 1 to len(string(listnum))            liststr = string(listnum)            list[n] = liststr[n]       next        for perm = 1 to fact(len(list))            numstr = substr(list2str(list), nl, "")            num1 = number(left(numstr,len(numstr)/2))            num2 = number(right(numstr,len(numstr)/2))            if (listnum = num1 * num2)                for n = 1 to len(total)                     if (num1 = total[n][2] and num2 = total[n][1]) or                         (num1 = total[n][1] and num2 = total[n][2])                         flag = 0                     ok               next               if flag = 1                   sum = sum + 1                   total[sum][1] = num1                   total[sum][2] = num2                                   see "" + listnum + ": [" + num1 + "," + num2 + "]" + nl                ok             ok            nextPermutation(list)       next func nextPermutation(a)     elementcount = len(a)     if elementcount < 1 then return ok     pos = elementcount-1     while a[pos] >= a[pos+1]            pos -= 1           if pos <= 0 permutationReverse(a, 1, elementcount)              return ok     end     last = elementcount     while a[last] <= a[pos]           last -= 1     end     temp = a[pos]     a[pos] = a[last]     a[last] = temp     permutationReverse(a, pos+1, elementcount)  func permutationReverse a, first, last      while first < last            temp = a[first]            a[first] = a[last]            a[last] = temp            first += 1            last -= 1      end func fact(nr)        if nr = 1            return 1         else           return nr * fact(nr-1)        ok func newlist(x,y)        if isstring(x) x=0+x ok        if isstring(y) y=0+y ok        alist = list(x)        for t in alist              t = list(y)        next        return alist `

Output:

```1260:	[21,60]
1395:	[15,93]
1435:	[35,41]
1530:	[30,51]
1827:	[21,87]
2187:	[27,81]
6880:	[80,86]
102510:	[201,510]
104260:	[260,401]
105210:	[210,501]
105264:	[204,516]
105750:	[150,705]
108135:	[135,801]
110758:	[158,701]
115672:	[152,761]
116725:	[161,725]
117067:	[167,701]
118440:	[141,840]
123354:	[231,534]
124483:	[281,443]
125248:	[152,824]
125433:	[231,543]
125460:	[204,615]
[246,510]
125500:	[251,500]
126027:	[201,627]
```

## Ruby

`def factor_pairs n  first = n / (10 ** (n.to_s.size / 2) - 1)  (first .. n ** 0.5).map { |i| [i, n / i] if n % i == 0 }.compactend def vampire_factors n  return [] if n.to_s.size.odd?  half = n.to_s.size / 2  factor_pairs(n).select do |a, b|    a.to_s.size == half && b.to_s.size == half &&    [a, b].count {|x| x%10 == 0} != 2          &&    "#{a}#{b}".chars.sort == n.to_s.chars.sort  endend i = vamps = 0until vamps == 25  vf = vampire_factors(i += 1)  unless vf.empty?    puts "#{i}:\t#{vf}"    vamps += 1  endend [16758243290880, 24959017348650, 14593825548650].each do |n|  if (vf = vampire_factors n).empty?    puts "#{n} is not a vampire number!"  else    puts "#{n}:\t#{vf}"  endend`
Output:
```1260:	[[21, 60]]
1395:	[[15, 93]]
1435:	[[35, 41]]
1530:	[[30, 51]]
1827:	[[21, 87]]
2187:	[[27, 81]]
6880:	[[80, 86]]
102510:	[[201, 510]]
104260:	[[260, 401]]
105210:	[[210, 501]]
105264:	[[204, 516]]
105750:	[[150, 705]]
108135:	[[135, 801]]
110758:	[[158, 701]]
115672:	[[152, 761]]
116725:	[[161, 725]]
117067:	[[167, 701]]
118440:	[[141, 840]]
120600:	[[201, 600]]
123354:	[[231, 534]]
124483:	[[281, 443]]
125248:	[[152, 824]]
125433:	[[231, 543]]
125460:	[[204, 615], [246, 510]]
125500:	[[251, 500]]
16758243290880:	[[1982736, 8452080], [2123856, 7890480], [2751840, 6089832], [2817360, 5948208]]
24959017348650:	[[2947050, 8469153], [2949705, 8461530], [4125870, 6049395], [4129587, 6043950], [4230765, 5899410]]
14593825548650 is not a vampire number!
```

## Scala

Works with: Scala version 2.9.1
`import Stream._import math._import scala.collection.mutable.ListBuffer object VampireNumbers extends App {  val elapsed: (=> Unit) => Long = f => {val s = System.currentTimeMillis; f; (System.currentTimeMillis - s)/1000}   val sexp = from(1, 2)   // stream of integer: 1,3,5,7, ...  val rs: Stream[Int] => Stream[Pair[Long,Long]] = exps => Pair(pow(10,exps.head).toLong,(pow(10,exps.head)*10-1).toLong)#::rs(exps.tail)  val srs = rs(sexp)   // stream of ranges: [10..99], [1000..9999], [100000..999999], ...  val cs: Stream[Pair[Long,Long]] => Stream[Long] = rs => (rs.head._1 to rs.head._2).toStream#:::cs(rs.tail)  val scs = cs(srs)   // stream of candidates: 10,11,..,99,1000,1001,..,9999, ...  val it = scs.iterator   val checkVN: Long => Pair[Long,Seq[Pair[Long,Long]]] = n => {    val check: Pair[Long,Long] => Pair[Long,Long] = p => {      val len: Long => Int = n => n.toString.size      val (a,b) = p      if ((a%10==0)&&(b%10==0)) Pair(0,0) else       if (len(a) != len(b)) Pair(0,0) else       if (n.toString.toList.diff(a.toString.toList++b.toString.toList)!=Nil) Pair(0,0) else p    }    Pair(n,(pow(10,log10(sqrt(n).toLong).toLong).toLong+1 to sqrt(n).toLong).filter{i=>n%i==0}     .map {fac =>Pair(fac,n/fac)}.map {p => check(p)}.filter {p => p._1 != 0})  }   val et = elapsed {    val lb = new ListBuffer[Pair[Long,Seq[Pair[Long,Long]]]]    while ((lb.size<25)&&(it.hasNext)) {      checkVN(it.next) match {        case (n, Seq()) =>         case p          => lb += p      }    }     lb.toList.zipWithIndex.foreach {p =>      println(p._2+1+": "+p._1._1+(p._1._2:\"")((x,y)=>" = "+x._1+" x "+x._2+y))    }    println     List(16758243290880L, 24959017348650L, 14593825548650L)      .map {checkVN(_)}      .foreach {         case (n, Seq()) => println(n+" is not vampiric")         case p => println(p._1+(p._2:\"")((x,y)=>" = "+x._1+" x "+x._2+y))       }  }   println("\n"+"elapsed time: "+et+" seconds")}`

Output:

```1: 1260 = 21 x 60
2: 1395 = 15 x 93
3: 1435 = 35 x 41
4: 1530 = 30 x 51
5: 1827 = 21 x 87
6: 2187 = 27 x 81
7: 6880 = 80 x 86
8: 102510 = 201 x 510
9: 104260 = 260 x 401
10: 105210 = 210 x 501
11: 105264 = 204 x 516
12: 105750 = 150 x 705
13: 108135 = 135 x 801
14: 110758 = 158 x 701
15: 115672 = 152 x 761
16: 116725 = 161 x 725
17: 117067 = 167 x 701
18: 118440 = 141 x 840
19: 120600 = 201 x 600
20: 123354 = 231 x 534
21: 124483 = 281 x 443
22: 125248 = 152 x 824
23: 125433 = 231 x 543
24: 125460 = 204 x 615 = 246 x 510
25: 125500 = 251 x 500

16758243290880 = 1982736 x 8452080 = 2123856 x 7890480 = 2751840 x 6089832 = 2817360 x 5948208
24959017348650 = 2947050 x 8469153 = 2949705 x 8461530 = 4125870 x 6049395 = 4129587 x 6043950 = 4230765 x 5899410
14593825548650 is not vampiric

elapsed time: 11 seconds```

## Sidef

`func is_vampire (n) {    return [] if n.ilog10.is_even     var l1 = n.isqrt.ilog10.ipow10    var l2 = n.isqrt     var s = n.digits.sort.join     gather {        n.divisors.each { |d|             d < l1 && next            d > l2 && break             var t = n/d             next if (d%%10 && t%%10)            next if ("#{d}#{t}".sort != s)             take([d, t])        }    }} say "First 25 Vampire Numbers:" with (1) { |i|    for (var n = 1; i <= 25; ++n) {        var fangs = is_vampire(n)        printf("%2d. %6s : %s\n", i++, n, fangs.join(' ')) if fangs    }} say "\nIndividual tests:" [16758243290880, 24959017348650, 14593825548650].each { |n|    var fangs = is_vampire(n)    say "#{n}: #{fangs ? fangs.join(', ') : 'is not a vampire number'}"}`
Output:
```First 25 Vampire Numbers:
1.   1260 : [21, 60]
2.   1395 : [15, 93]
3.   1435 : [35, 41]
4.   1530 : [30, 51]
5.   1827 : [21, 87]
6.   2187 : [27, 81]
7.   6880 : [80, 86]
8. 102510 : [201, 510]
9. 104260 : [260, 401]
10. 105210 : [210, 501]
11. 105264 : [204, 516]
12. 105750 : [150, 705]
13. 108135 : [135, 801]
14. 110758 : [158, 701]
15. 115672 : [152, 761]
16. 116725 : [161, 725]
17. 117067 : [167, 701]
18. 118440 : [141, 840]
19. 120600 : [201, 600]
20. 123354 : [231, 534]
21. 124483 : [281, 443]
22. 125248 : [152, 824]
23. 125433 : [231, 543]
24. 125460 : [204, 615] [246, 510]
25. 125500 : [251, 500]

Individual tests:
16758243290880: [1982736, 8452080], [2123856, 7890480], [2751840, 6089832], [2817360, 5948208]
24959017348650: [2947050, 8469153], [2949705, 8461530], [4125870, 6049395], [4129587, 6043950], [4230765, 5899410]
14593825548650: is not a vampire number
```

## Swift

`import Foundation func vampire<T>(n: T) -> [(T, T)] where T: BinaryInteger, T.Stride: SignedInteger {  let strN = String(n).sorted()  let fangLength = strN.count / 2  let start = T(pow(10, Double(fangLength - 1)))  let end = T(Double(n).squareRoot())   var fangs = [(T, T)]()   for i in start...end where n % i == 0 {    let quot = n / i     guard i % 10 != 0 || quot % 10 != 0 else {      continue    }     if "\(i)\(quot)".sorted() == strN {      fangs.append((i, quot))    }  }   return fangs} var count = 0var i = 1.0 while count < 25 {  let start = Int(pow(10, i))  let end = start * 10   for num in start...end {    let fangs = vampire(n: num)     guard !fangs.isEmpty else { continue }     count += 1     print("\(num) is a vampire number with fangs: \(fangs)")     guard count != 25 else { break }  }   i += 2} for (vamp, fangs) in [16758243290880, 24959017348650, 14593825548650].lazy.map({ (\$0, vampire(n: \$0)) }) {  if fangs.isEmpty {    print("\(vamp) is not a vampire number")  } else {    print("\(vamp) is a vampire number with fangs: \(fangs)")  }}`
Output:
```1260 is a vampire number with fangs: [(21, 60)]
1395 is a vampire number with fangs: [(15, 93)]
1435 is a vampire number with fangs: [(35, 41)]
1530 is a vampire number with fangs: [(30, 51)]
1827 is a vampire number with fangs: [(21, 87)]
2187 is a vampire number with fangs: [(27, 81)]
6880 is a vampire number with fangs: [(80, 86)]
102510 is a vampire number with fangs: [(201, 510)]
104260 is a vampire number with fangs: [(260, 401)]
105210 is a vampire number with fangs: [(210, 501)]
105264 is a vampire number with fangs: [(204, 516)]
105750 is a vampire number with fangs: [(150, 705)]
108135 is a vampire number with fangs: [(135, 801)]
110758 is a vampire number with fangs: [(158, 701)]
115672 is a vampire number with fangs: [(152, 761)]
116725 is a vampire number with fangs: [(161, 725)]
117067 is a vampire number with fangs: [(167, 701)]
118440 is a vampire number with fangs: [(141, 840)]
120600 is a vampire number with fangs: [(201, 600)]
123354 is a vampire number with fangs: [(231, 534)]
124483 is a vampire number with fangs: [(281, 443)]
125248 is a vampire number with fangs: [(152, 824)]
125433 is a vampire number with fangs: [(231, 543)]
125460 is a vampire number with fangs: [(204, 615), (246, 510)]
125500 is a vampire number with fangs: [(251, 500)]
16758243290880 is a vampire number with fangs: [(1982736, 8452080), (2123856, 7890480), (2751840, 6089832), (2817360, 5948208)]
24959017348650 is a vampire number with fangs: [(2947050, 8469153), (2949705, 8461530), (4125870, 6049395), (4129587, 6043950), (4230765, 5899410)]
14593825548650 is not a vampire number```

## Tcl

Translation of: Ruby
`proc factorPairs {n {from 2}} {    set result [list 1 \$n]    if {\$from<=1} {set from 2}    for {set i \$from} {\$i<=sqrt(\$n)} {incr i} {	if {\$n%\$i} {} {lappend result \$i [expr {\$n/\$i}]}    }    return \$result} proc vampireFactors {n} {    if {[string length \$n]%2} return    set half [expr {[string length \$n]/2}]    set digits [lsort [split \$n ""]]    set result {}    foreach {a b} [factorPairs \$n [expr {10**\$half/10}]] {	if {	    [string length \$a]==\$half && [string length \$b]==\$half &&	    (\$a%10 || \$b%10) && \$digits eq [lsort [split \$a\$b ""]]	} then {	    lappend result [list \$a \$b]	}    }    return \$result}`

Demonstrating:

`# A nicer way to print the evidence of vampire-nessproc printVampire {n pairs} {    set out "\${n}:"    foreach p \$pairs {	append out " \[[join \$p {, }]\]"    }    puts \$out}set n 0for {set i 0} {\$i < 25} {incr i} {    while 1 {	if {[llength [set vamps [vampireFactors [incr n]]]]} {	    printVampire \$n \$vamps	    break	}    }}puts ""foreach n {16758243290880 24959017348650 14593825548650} {    if {[llength [set vamps [vampireFactors \$n]]]} {	printVampire \$n \$vamps    } else {	puts "\$n is not a vampire number"    }}`
Output:
```1260: [21, 60]
1395: [15, 93]
1435: [35, 41]
1530: [30, 51]
1827: [21, 87]
2187: [27, 81]
6880: [80, 86]
102510: [201, 510]
104260: [260, 401]
105210: [210, 501]
105264: [204, 516]
105750: [150, 705]
108135: [135, 801]
110758: [158, 701]
115672: [152, 761]
116725: [161, 725]
117067: [167, 701]
118440: [141, 840]
120600: [201, 600]
123354: [231, 534]
124483: [281, 443]
125248: [152, 824]
125433: [231, 543]
125460: [204, 615] [246, 510]
125500: [251, 500]

16758243290880: [1982736, 8452080] [2123856, 7890480] [2751840, 6089832] [2817360, 5948208]
24959017348650: [2947050, 8469153] [2949705, 8461530] [4125870, 6049395] [4129587, 6043950] [4230765, 5899410]
14593825548650 is not a vampire number
```

## zkl

`fcn fangs(N){ //-->if Vampire number: (N,(a,b,c,...)), where a*x==N   var [const] tens=[0 .. 18].pump(List,(10.0).pow,"toInt");    (half:=N.numDigits) : if (_.isOdd) return(T);;   half/=2; digits:=N.toString().sort();   lo:=tens[half-1].max((N+tens[half])/(tens[half]));   hi:=(N/lo).min(N.toFloat().sqrt());   fs:=[lo .. hi].filter('wrap(n){      N%n==0 and (n%10!=0 or (N/n)%10!=0) and      (n.toString()+(N/n).toString()).sort()==digits   });   fs and T(N,fs) or T;}`
`fcn vampiric(fangs,n=Void){   if(not fangs) return(n,"Not a Vampire number");   v:=fangs[0]; T(v,fangs[1].apply('wrap(n){T(n,v/n)})) } T(16758243290880, 24959017348650, 14593825548650).pump(Console.println,fcn(n){"%d: %s".fmt(vampiric(fangs(n),n).xplode())}); (0).walker(*).tweak(fangs).filter(26).pump(Console.println,vampiric);`
Output:
```16758243290880: L(L(1982736,8452080),L(2123856,7890480),L(2751840,6089832),L(2817360,5948208))
24959017348650: L(L(2947050,8469153),L(2949705,8461530),L(4125870,6049395),L(4129587,6043950),L(4230765,5899410))
14593825548650: Not a Vampire number
L(1260,L(L(21,60)))
L(1395,L(L(15,93)))
L(1435,L(L(35,41)))
L(1530,L(L(30,51)))
L(1827,L(L(21,87)))
L(2187,L(L(27,81)))
L(6880,L(L(80,86)))
L(102510,L(L(201,510)))
L(104260,L(L(260,401)))
L(105210,L(L(210,501)))
L(105264,L(L(204,516)))
L(105750,L(L(150,705)))
L(108135,L(L(135,801)))
L(110758,L(L(158,701)))
L(115672,L(L(152,761)))
L(116725,L(L(161,725)))
L(117067,L(L(167,701)))
L(118440,L(L(141,840)))
L(120600,L(L(201,600)))
L(123354,L(L(231,534)))
L(124483,L(L(281,443)))
L(125248,L(L(152,824)))
L(125433,L(L(231,543)))
L(125460,L(L(204,615),L(246,510)))
L(125500,L(L(251,500)))
L(126027,L(L(201,627)))
```