Magic numbers
You are encouraged to solve this task according to the task description, using any language you may know.
Magic numbers are polydivisible numbers in base 10. A polydivisible number is an m digit number where the first n digits are evenly divisible by n for all n from 1 to m.
E.G. The number 1868587 is a magic number (is polydivisible in base 10.)
1 ÷ 1 = 1 18 ÷ 2 = 9 186 ÷ 3 = 62 1868 ÷ 4 = 467 18685 ÷ 5 = 3737 186858 ÷ 6 = 31143 1868587 ÷ 7 = 266941
There is a finite number of magic numbers.
- Task
- Write a routine (subroutine, function, procedure, generator, whatever it may be called in your language) to find magic numbers.
- Use that routine to find and display how many magic numbers exist.
- Use that routine to find and display the largest possible magic number.
- Count and display how many magic numbers have 1 digit, 2 digits, 3 digits, ... for all magic numbers.
- Find and display all of the magic numbers that are minimally pandigital in 1 through 9. (Contains each digit but only once.)
- Find and display all of the magic numbers that are minimally pandigital in 0 through 9.
Zero (0) may or may not be included as a magic number. For this task, include zero.
- See also
ALGOL 68
Uses Algol 68G's LONG LONG INT, which has programmer definable precision, the default is sufficient for this task.
BEGIN # count magic numbers: numbers divisible by the count of digits and #
# each left substring is also divisible by the count of its digits #
# returns the magic numbers of length m length that can be formed by #
# adding a digit to the elements of prev m #
PROC next magic = ( []LONG LONG INT prev m, INT m length )[]LONG LONG INT:
BEGIN
FLEX[ 1 : 2 000 ]LONG LONG INT m;
INT m pos := 0;
FOR i FROM LWB prev m TO UPB prev m DO
LONG LONG INT n := prev m[ i ] * 10;
FOR d FROM 0 BY IF ODD m length THEN 1 ELSE 2 FI TO 9 DO
IF ( n + d ) MOD m length = 0 THEN
IF m pos >= UPB m THEN
# need a bigger magic number buffer #
[ 1 : UPB m + 1000 ]LONG LONG INT new m;
new m[ 1 : UPB m ] := m;
m := new m
FI;
m[ m pos +:= 1 ] := n + d
FI
OD
OD;
m[ 1 : m pos ]
END # next magic # ;
# returns TRUE if n is pandigital (1-9), FALSE otherwise #
PROC is pandigital1 = ( LONG LONG INT n )BOOL:
BEGIN
INT v := SHORTEN SHORTEN n;
[ 0 : 9 ]INT digit count := []INT( 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 )[ AT 0 ];
WHILE digit count[ v MOD 10 ] +:= 1;
( v OVERAB 10 ) > 0
DO SKIP OD;
BOOL result := digit count[ 0 ] = 0;
FOR i FROM 1 TO 9 WHILE result := digit count[ i ] = 1 DO SKIP OD;
result
END # is pandigital1 # ;
# find the magic numbers #
print( ( "Magic number counts by number of digits:", newline ) );
INT m count := 0; # total number of magic numbers #
INT d count := 1; # number of digits #
FLEX[ 1 : 10 ]LONG LONG INT magic := ( 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 );
FLEX[ 1 : 0 ]LONG LONG INT magic9;
LONG LONG INT max magic := -1;
WHILE UPB magic >= LWB magic DO
print( ( whole( d count, -5 ), ": ", whole( UPB magic, -9 ), newline ) );
m count +:= UPB magic;
max magic := magic[ UPB magic ];
IF d count = 1 THEN
# exclude 0 from the 1 digit magic numbers to find the 2 digit #
magic := ( 1, 2, 3, 4, 5, 6, 7, 8, 9 )
ELIF d count = 9 THEN
# save the 9 digit magic numbers so we can find the pandigitals #
magic9 := magic
FI;
magic := next magic( magic, d count +:= 1 )
OD;
print( ( "Total:", whole( m count, -10 ), " magic numbers", newline ) );
print( ( "Largest is ", whole( max magic, 0 ), newline ) );
# find the minimally pandigital magic numbers #
[ 1 : UPB magic9 ]LONG LONG INT pd magic;
INT pd pos := 0;
FOR i FROM LWB pd magic TO UPB pd magic DO
IF is pandigital1( magic9[ i ] ) THEN
pd magic[ pd pos +:= 1 ] := magic9[ i ]
FI
OD;
print( ( "Minimally pandigital 1-9 magic numbers: " ) );
FOR i TO pd pos DO
print( ( whole( pd magic[ i ], 0 ) ) )
OD;
print( ( newline ) );
print( ( "Minimally pandigital 0-9 magic numbers: " ) );
FOR i TO pd pos DO
print( ( whole( pd magic[ i ] * 10, 0 ) ) )
OD;
print( ( newline ) )
END
- Output:
Magic number counts by number of digits: 1: 10 2: 45 3: 150 4: 375 5: 750 6: 1200 7: 1713 8: 2227 9: 2492 10: 2492 11: 2225 12: 2041 13: 1575 14: 1132 15: 770 16: 571 17: 335 18: 180 19: 90 20: 44 21: 18 22: 12 23: 6 24: 3 25: 1 Total: 20457 magic numbers Largest is 3608528850368400786036725 Minimally pandigital 1-9 magic numbers: 381654729 Minimally pandigital 0-9 magic numbers: 3816547290
AWK
function lmod(n, d, i, l, r) {
l = 15 - length(d - 1)
for (i = 1; i <= d; i += l) r = (r substr(n, i, l)) % d
return r
}
function is_pandigital(d, n) {
while (d < 10) if (!index(n, d++)) return 0
return 1
}
BEGIN {
do {
l = length(n = res[++i]) + 1
for (d = (l - lmod(n "0", l)) % l; d < 10; d += l)
res[++o] = n d
} while (i != o)
print "found " o " magic numbers"
print "the largest one is " res[o]
print "count by number of digits:"
l = 0
for (i = 1; i <= o; ++i) {
if ((d = length(m = res[i])) == l) {
++n
} else {
if (l) printf "%u:%u ", l, n
n = 1
l = d
}
if (l == 9 && is_pandigital(1, m))
pd1 = pd1 " " m
if (l == 10 && is_pandigital(0, m))
pd0 = pd0 " " m
}
printf "%u:%u\n", l, n
print "minimally pandigital in 1..9:" pd1
print "minimally pandigital in 0..9:" pd0
}
- Output:
found 20457 magic numbers the largest one is 3608528850368400786036725 count by number of digits: 1:10 2:45 3:150 4:375 5:750 6:1200 7:1713 8:2227 9:2492 10:2492 11:2225 12:2041 13:1575 14:1132 15:770 16:571 17:335 18:180 19:90 20:44 21:18 22:12 23:6 24:3 25:1 minimally pandigital in 1..9: 381654729 minimally pandigital in 0..9: 3816547290
BASIC
FreeBASIC
Function lmod(n As String, d As Integer) As Ulongint
Dim As Ulongint r = 0
For i As Integer = 1 To Len(n)
r = (r * 10 + Val(Mid(n, i, 1))) Mod d
Next i
Return r
End Function
Function isPandigital(d As Integer, n As String) As Boolean
While d < 10
If Instr(n, Trim(Str(d))) = 0 Then Return False
d += 1
Wend
Return True
End Function
Dim Shared As String res(1 To 1000000)
Dim As Integer i, o, l, d, nn
Dim As String pd1, pd0, n, m
i = 0 : o = 0
Do
n = res(i + 1)
l = Len(n) + 1
For d = 0 To 9
If (lmod(n & Trim(Str(d)), l) = 0) Then
o += 1
res(o) = n & Trim(Str(d))
End If
Next d
i += 1
Loop Until i = o
Print "Found "; o; " magic numbers"
Print !"\nThe largest one is "; res(o)
Print !"\ncount by number of digits:"
l = 0
For i = 1 To o
m = res(i)
d = Len(m)
If d = l Then
nn += 1
Else
If l Then Print Using "## : &"; l; nn
nn = 1
l = d
End If
If l = 9 And isPandigital(1, m) Then pd1 &= " " & m
If l = 10 And isPandigital(0, m) Then pd0 &= " " & m
Next i
Print Using "## : &"; l; nn
Print !"\nminimally pandigital in 1..9:" & pd1
Print "minimally pandigital in 0..9:" & pd0
Sleep
- Output:
Found 20457 magic numbers The largest one is 3608528850368400786036725 count by number of digits: 1 : 10 2 : 45 3 : 150 4 : 375 5 : 750 6 : 1200 7 : 1713 8 : 2227 9 : 2492 10 : 2492 11 : 2225 12 : 2041 13 : 1575 14 : 1132 15 : 770 16 : 571 17 : 335 18 : 180 19 : 90 20 : 44 21 : 18 22 : 12 23 : 6 24 : 3 25 : 1 minimally pandigital in 1..9: 381654729 minimally pandigital in 0..9: 3816547290
QB64
Dim Shared res(1 To 1000000) As String
Dim As Long i, o, l, d, nn
Dim As String pd1, pd0, n, m
i = 0: o = 0
Do
n = res(i + 1)
l = Len(n) + 1
For d = 0 To 9
If (lmod(n + LTrim$(RTrim$(Str$(d))), l) = 0) Then
o = o + 1
res(o) = n + LTrim$(RTrim$(Str$(d)))
End If
Next d
i = i + 1
Loop Until i = o
Print "Found "; o; " magic numbers"
Print Chr$(10) + "The largest one is "; res(o)
Print Chr$(10) + "count by number of digits:"
l = 0
For i = 1 To o
m = res(i)
d = Len(m)
If d = l Then
nn = nn + 1
Else
If l Then Print Using "## : "; l;: Print nn
nn = 1
l = d
End If
If l = 9 And isPandigital(1, m) Then pd1 = pd1 + " " + m
If l = 10 And isPandigital(0, m) Then pd0 = pd0 + " " + m
Next i
Print Using "## : "; l;: Print nn
Print Chr$(10) + "minimally pandigital in 1..9:" + pd1
Print "minimally pandigital in 0..9:" + pd0
Function lmod& (n As String, d As Integer)
r& = 0
For i& = 1 To Len(n)
r = (r * 10 + Val(Mid$(n, i&, 1))) Mod d
Next i&
lmod = r
End Function
Function isPandigital% (d As Integer, n As String)
Dim i As Integer
For i = d To 9
If InStr(n, LTrim$(RTrim$(Str$(i)))) = 0 Then isPandigital% = 0: Exit Function
Next i
isPandigital% = -1
End Function
- Output:
Same as FreeBASIC entry.
C++
#include <array>
#include <iostream>
#include <numeric>
#include <vector>
#include <boost/multiprecision/cpp_int.hpp>
using boost::multiprecision::uint128_t;
class magic_number_generator {
public:
magic_number_generator() : magic_(10) {
std::iota(magic_.begin(), magic_.end(), 0);
}
bool next(uint128_t& n);
public:
std::vector<uint128_t> magic_;
size_t index_ = 0;
int digits_ = 2;
};
bool magic_number_generator::next(uint128_t& n) {
if (index_ == magic_.size()) {
std::vector<uint128_t> magic;
for (uint128_t m : magic_) {
if (m == 0)
continue;
uint128_t n = 10 * m;
for (int d = 0; d < 10; ++d, ++n) {
if (n % digits_ == 0)
magic.push_back(n);
}
}
index_ = 0;
++digits_;
magic_ = std::move(magic);
}
if (magic_.empty())
return false;
n = magic_[index_++];
return true;
}
std::array<int, 10> get_digits(uint128_t n) {
std::array<int, 10> result = {};
for (; n > 0; n /= 10)
++result[static_cast<int>(n % 10)];
return result;
}
int main() {
int count = 0, dcount = 0;
uint128_t magic = 0, p = 10;
std::vector<int> digit_count;
std::array<int, 10> digits0 = {1,1,1,1,1,1,1,1,1,1};
std::array<int, 10> digits1 = {0,1,1,1,1,1,1,1,1,1};
std::vector<uint128_t> pandigital0, pandigital1;
for (magic_number_generator gen; gen.next(magic);) {
if (magic >= p) {
p *= 10;
digit_count.push_back(dcount);
dcount = 0;
}
auto digits = get_digits(magic);
if (digits == digits0)
pandigital0.push_back(magic);
else if (digits == digits1)
pandigital1.push_back(magic);
++count;
++dcount;
}
digit_count.push_back(dcount);
std::cout << "There are " << count << " magic numbers.\n\n";
std::cout << "The largest magic number is " << magic << ".\n\n";
std::cout << "Magic number count by digits:\n";
for (int i = 0; i < digit_count.size(); ++i)
std::cout << i + 1 << '\t' << digit_count[i] << '\n';
std::cout << "\nMagic numbers that are minimally pandigital in 1-9:\n";
for (auto m : pandigital1)
std::cout << m << '\n';
std::cout << "\nMagic numbers that are minimally pandigital in 0-9:\n";
for (auto m : pandigital0)
std::cout << m << '\n';
}
- Output:
There are 20457 magic numbers. The largest magic number is 3608528850368400786036725. Magic number count by digits: 1 10 2 45 3 150 4 375 5 750 6 1200 7 1713 8 2227 9 2492 10 2492 11 2225 12 2041 13 1575 14 1132 15 770 16 571 17 335 18 180 19 90 20 44 21 18 22 12 23 6 24 3 25 1 Magic numbers that are minimally pandigital in 1-9: 381654729 Magic numbers that are minimally pandigital in 0-9: 3816547290
EasyLang
func[] bnmul a[] b .
for d in a[]
h = c + d * b
r[] &= h mod 10000000
c = h div 10000000
.
if c > 0
r[] &= c
.
return r[]
.
func bnmod a[] b .
for ia = len a[] downto 1
m = (m * 10000000 + a[ia]) mod b
.
return m
.
func$ str bn[] .
s$ = bn[$]
for i = len bn[] - 1 downto 1
h$ = bn[i]
s$ &= substr "0000000" 1 (7 - len h$) & h$
.
return s$
.
func bnlen bn[] .
if bn[] = [ 0 ]
return 1
.
return (len bn[] - 1) * 7 + floor log10 bn[$] + 1
.
global mn[][] .
proc getmagnums . .
i = 1
n[] = [ 0 ]
repeat
l = bnlen n[]
for dig = (l - bnmod n[] l) mod l step l to 9
mn[][] &= n[]
mn[$][1] += dig
.
i += 1
until i = len mn[][]
n[] = bnmul mn[i][] 10
.
.
getmagnums
#
proc show . .
print len mn[][] & " magic numbers"
print str mn[$][] & " is the largest"
len ndigs[] 25
min = 1 / 0
for mi to len mn[][]
n[] = mn[mi][]
ndig = bnlen n[]
ndigs[ndig] += 1
if ndig = 9
s$ = str n[]
for i = 1 to 9
if strpos s$ i = 0
s$ = "999999999"
.
.
min = lower min number s$
.
.
print "count by number of digits:"
for i to len ndigs[]
write i & ":" & ndigs[i] & " "
.
print ""
print min & " is minimal pandigital in 1..9"
print min & 0 & " is minimal pandigital in 0..9"
.
show
- Output:
20457 magic numbers 3608528850368400786036725 is the largest count by number of digits: 1:10 2:45 3:150 4:375 5:750 6:1200 7:1713 8:2227 9:2492 10:2492 11:2225 12:2041 13:1575 14:1132 15:770 16:571 17:335 18:180 19:90 20:44 21:18 22:12 23:6 24:3 25:1 381654729 is minimal pandigital in 1..9 3816547290 is minimal pandigital in 0..9
F#
// Magic numbers. Nigel Galloway: February 10th., 2023
let digs=[|0..10|]|>Array.map(System.UInt128.CreateChecked)
let fN n g=n|>List.collect(fun n->let n=n*digs[10] in [for g in digs[0..9]->n+g]|>List.filter(fun n->n%g=digs[0]))
let fG (n:int []) g=let rec fN g=if g<digs[10] then n[int g]<-n[int g]-1 else n[int(g%digs[10])]<-n[int(g%digs[10])]-1; fN (g/digs[10])
fN g; Array.forall ((=)0) n
let magic=Array.append [|[digs[0]..digs[9]]|] (Array.unfold(fun(n,g)->match n with []->None |n->let n=fN n g in Some(n,(n,g+digs[1])))([digs[1]..digs[9]],digs[2]))
printfn $"There are %d{magic|>Array.sumBy(List.length)} Magic numbers"
magic|>Array.iteri(fun n g->printfn "There are %d magic numbers of length %d" (List.length g) (n+1))
printfn $"Largest magic number is %A{magic.[magic.Length-2]|>List.max}"
printf "Minimally pan-digital(1..9) magic numbers are: "; magic[8]|>List.filter(fun n->fG [|0;1;1;1;1;1;1;1;1;1|] n)|>List.iter(printf "%A ");printfn ""
printf "Minimally pan-digital(1..9) magic numbers are: "; magic[9]|>List.filter(fun n->fG [|1;1;1;1;1;1;1;1;1;1|] n)|>List.iter(printf "%A ");printfn ""9
- Output:
There are 20457 Magic numbers There are 10 magic numbers of length 1 There are 45 magic numbers of length 2 There are 150 magic numbers of length 3 There are 375 magic numbers of length 4 There are 750 magic numbers of length 5 There are 1200 magic numbers of length 6 There are 1713 magic numbers of length 7 There are 2227 magic numbers of length 8 There are 2492 magic numbers of length 9 There are 2492 magic numbers of length 10 There are 2225 magic numbers of length 11 There are 2041 magic numbers of length 12 There are 1575 magic numbers of length 13 There are 1132 magic numbers of length 14 There are 770 magic numbers of length 15 There are 571 magic numbers of length 16 There are 335 magic numbers of length 17 There are 180 magic numbers of length 18 There are 90 magic numbers of length 19 There are 44 magic numbers of length 20 There are 18 magic numbers of length 21 There are 12 magic numbers of length 22 There are 6 magic numbers of length 23 There are 3 magic numbers of length 24 There are 1 magic numbers of length 25 There are 0 magic numbers of length 26 Largest magic number is 3608528850368400786036725 Minimally pan-digital(1..9) magic numbers are: 381654729 Minimally pan-digital(0..9) magic numbers are: 3816547290
J
Implementation:
ispdiv=: {{0= +/(# | 10 #. ])\ 10&#.inv y}}
{{
if. 0>nc<'pdivs' do.
pdivs=: {{
r=. 0,d=. 1 2 3 4 5 6 7 8 9x
while. #d do.
r=. r,d=. (#~ ispdiv"0), (10*d)+/i.10
end.
}}0
end.
}}0
Task:
#pdivs NB. quantity of these "magic' numbers"
20457
>./pdivs NB. largest of these "magic numbers"
3608528850368400786036725
(~.,. #/.~) #@":@> pdivs NB. tallies by digit count
1 10
2 45
3 150
4 375
5 750
6 1200
7 1713
8 2227
9 2492
10 2492
11 2225
12 2041
13 1575
14 1132
15 770
16 571
17 335
18 180
19 90
20 44
21 18
22 12
23 6
24 3
25 1
(#~ '123456789'&-:@(/:~)@":@>)pdivs
381654729
(#~ '0123456789'&-:@(/:~)@":@>)pdivs
3816547290
Java
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
public final class MagicNumbers {
public static void main(String[] args) {
List<BigInteger> magicNumbers = polydivisible(10);
System.out.println("There are " + magicNumbers.size() + " magic numbers.");
System.out.println("The largest magic number is " + magicNumbers.getLast());
System.out.println();
List<List<String>> magicLists = magicLists(magicNumbers);
System.out.println("Count of magic numbers by the number of digits:");
IntStream.range(0, magicLists.size()).forEach( i ->
System.out.println(String.format("%2d%s%5d", i + 1, ":", magicLists.get(i).size())) );
System.out.println();
System.out.print("Minimally pandigital 1-9 magic numbers: ");
magicLists.get(8).stream().filter( s -> isMinimallyPandigital(s, "1") ).forEach(System.out::print);
System.out.println();
System.out.print("Minimally pandigital 0-9 magic numbers: ");
magicLists.get(9).stream().filter( s -> isMinimallyPandigital(s, "0") ).forEach(System.out::print);
}
private static List<BigInteger> polydivisible(int base) {
List<BigInteger> magicNumbers = new ArrayList<BigInteger>();
List<BigInteger> previousNumbers = IntStream.range(1, base).mapToObj( i -> BigInteger.valueOf(i) )
.collect(Collectors.toList());
List<BigInteger> newNumbers = new ArrayList<BigInteger>();
BigInteger digitCount = BigInteger.TWO;
while ( ! previousNumbers.isEmpty() ) {
magicNumbers.addAll(previousNumbers);
for ( BigInteger prev : previousNumbers ) {
for ( int j = 0; j < base; j++ ) {
BigInteger number = prev.multiply(BigInteger.valueOf(base)).add(BigInteger.valueOf(j));
if ( number.mod(digitCount).signum() == 0 ) {
newNumbers.addLast(number);
}
}
}
previousNumbers = new ArrayList<BigInteger>(newNumbers);
newNumbers = new ArrayList<BigInteger>();
digitCount = digitCount.add(BigInteger.ONE);
}
magicNumbers.addFirst(BigInteger.ZERO);
return magicNumbers;
}
private static List<List<String>> magicLists(List<BigInteger> magicNumbers) {
List<List<String>> result = new ArrayList<List<String>>();
magicNumbers.stream().map( i -> i.toString() ).forEach( s -> {
if ( s.length() > result.size() ) {
result.addLast( new ArrayList<String>() );
}
result.get(s.length() - 1).addLast(s);
} );
return result;
}
private static boolean isMinimallyPandigital(String number, String startDigit) {
List<String> digits = number.chars().mapToObj( i -> String.valueOf(i - '0') )
.distinct().sorted().toList();
return digits.size() == 10 - Integer.valueOf(startDigit) && digits.getFirst().equals(startDigit);
}
}
- Output:
There are 20457 magic numbers. The largest magic number is 3608528850368400786036725 Count of magic numbers by the number of digits: 1: 10 2: 45 3: 150 4: 375 5: 750 6: 1200 7: 1713 8: 2227 9: 2492 10: 2492 11: 2225 12: 2041 13: 1575 14: 1132 15: 770 16: 571 17: 335 18: 180 19: 90 20: 44 21: 18 22: 12 23: 6 24: 3 25: 1 Minimally pandigital 1-9 magic numbers: 381654729 Minimally pandigital 0-9 magic numbers: 3816547290
jq
Adapted from Wren
Works with gojq, the Go implementation of jq, and with fq
The solution presented here depends on the unbounded-precision integer arithmetic of the Go implementations of jq, and the results shown can be generated by an invocation of the form:
gojq -nr -f magic-numbers.jq
def sum(s): reduce s as $x (0; .+$x);
# Emit all the polydivisibles in the form of an array of arrays
# such that the numbers in .[i] are the polydivisibles of length i+1
def polydivisible:
def extend($n):
((. * 10) + range(0;10)) | select(. % $n == 0);
# input: an array of arrays, such that the numbers in .[i] are the polydivisibles of length i+1
def extend:
. as $in
| length as $n
| [$in[-1][] | extend($n+1)] as $x
| if $x|length == 0 then $in
else $in + [$x] | extend
end;
[[range(1;10)]] | extend;
def pandigital:
tostring | gsub("0";"") | explode | unique | length == 9;
# Select the pandigitals from .[$k]
# Input: an array as produced by polydivisible
# Output: an array
def pd($k):
.[$k] | map(select(pandigital));
def tasks:
polydivisible
| .[0] += [0]
| "There are \(sum(.[] | length)) magic numbers in total.",
"\nThe largest is \(.[-1][-1])",
"\nThere are:",
(range(0; length) as $i
| "\(.[$i]|length) with \($i + 1) digit\(if ($i == 0) then "" else "s" end)"),
( "\nAll magic numbers that are pan-digital in 1 through 9 with no repeats: ", pd(8)[] ),
( "\nAll magic numbers that are pan-digital in 0 through 9 with no repeats: ", pd(9)[] ) ;
tasks
- Output:
There are 20457 magic numbers in total. The largest is 3608528850368400786036725 There are: 10 with 1 digit 45 with 2 digits 150 with 3 digits 375 with 4 digits 750 with 5 digits 1200 with 6 digits 1713 with 7 digits 2227 with 8 digits 2492 with 9 digits 2492 with 10 digits 2225 with 11 digits 2041 with 12 digits 1575 with 13 digits 1132 with 14 digits 770 with 15 digits 571 with 16 digits 335 with 17 digits 180 with 18 digits 90 with 19 digits 44 with 20 digits 18 with 21 digits 12 with 22 digits 6 with 23 digits 3 with 24 digits 1 with 25 digits All magic numbers that are pan-digital in 1 through 9 with no repeats: 381654729 All magic numbers that are pan-digital in 0 through 9 with no repeats: 3816547290
Julia
function findmagics(maxdig = 26)
magics = [Int128[] for _ in 1:maxdig-1]
pushfirst!(magics, collect(one(Int128):9))
for n in 2:maxdig, i in magics[n - 1], j in 0:9
k = 10i + j
k % n == 0 && push!(magics[n], k)
end
pushfirst!(first(magics), 0) # zero is a one-digit magic number?
return magics
end
const magics = findmagics()
for (n, arr) in enumerate(magics)
println("There are $(length(arr)) magic numbers with $n digits",
isempty(arr) ? "." : " with the largest $(last(arr)).")
end
println("\nIn all, there are $(sum(map(length, magics))) magic numbers.\n")
println("Magic number(s) pan-digital in 1 through 9 with no repeats: ",
join(filter(n -> (d = digits(n); all(i -> count(==(i), d) == 1, 1:9)), magics[9])))
println("Magic number(s) pan-digital in 0 through 9 with no repeats: ",
join(filter(n -> (d = digits(n); all(i -> count(==(i), d) == 1, 0:9)), magics[10])))
- Output:
There are 10 magic numbers with 1 digits with the largest 9. There are 45 magic numbers with 2 digits with the largest 98. There are 150 magic numbers with 3 digits with the largest 987. There are 375 magic numbers with 4 digits with the largest 9876. There are 750 magic numbers with 5 digits with the largest 98765. There are 1200 magic numbers with 6 digits with the largest 987654. There are 1713 magic numbers with 7 digits with the largest 9876545. There are 2227 magic numbers with 8 digits with the largest 98765456. There are 2492 magic numbers with 9 digits with the largest 987654564. There are 2492 magic numbers with 10 digits with the largest 9876545640. There are 2225 magic numbers with 11 digits with the largest 98765456405. There are 2041 magic numbers with 12 digits with the largest 987606963096. There are 1575 magic numbers with 13 digits with the largest 9876069630960. There are 1132 magic numbers with 14 digits with the largest 98760696309604. There are 770 magic numbers with 15 digits with the largest 987606963096045. There are 571 magic numbers with 16 digits with the largest 9876062430364208. There are 335 magic numbers with 17 digits with the largest 98485872309636009. There are 180 magic numbers with 18 digits with the largest 984450645096105672. There are 90 magic numbers with 19 digits with the largest 9812523240364656789. There are 44 magic numbers with 20 digits with the largest 96685896604836004260. There are 18 magic numbers with 21 digits with the largest 966858966048360042609. There are 12 magic numbers with 22 digits with the largest 9668589660483600426096. There are 6 magic numbers with 23 digits with the largest 72645656402410567240820. There are 3 magic numbers with 24 digits with the largest 402852168072900828009216. There are 1 magic numbers with 25 digits with the largest 3608528850368400786036725. There are 0 magic numbers with 26 digits. In all, there are 20457 magic numbers. Magic number(s) pan-digital in 1 through 9 with no repeats: 381654729 Magic number(s) pan-digital in 0 through 9 with no repeats: 3816547290
Nim
import std/[algorithm, sequtils, strformat, strutils]
import integers
iterator magicNumbers(): tuple[length: int; value: Integer] =
## Yield the lengths and values of magic numbers.
var magics = toSeq(newInteger(1)..newInteger(9)) # Ignore 0 for now.
yield (1, newInteger(0))
var length = 1
while magics.len != 0:
for n in magics: yield (length, n)
var newMagics: seq[Integer]
inc length
for m in magics:
for d in 0..9:
let n = 10 * m + d
if n mod length == 0:
newMagics.add n
magics = move(newMagics)
func isMinimallyPandigital(n: Integer; start: char): bool =
## Return true if "n" is minimally pandigital in "start" through 9.
sorted($n) == toSeq(start..'9')
# Build list of magic numbers distributed by length.
var magicList: seq[seq[Integer]] = @[@[]]
var total = 0
for (length, n) in magicNumbers():
if length > magicList.high:
magicList.add @[]
magicList[^1].add n
inc total
echo &"Number of magic numbers: {insertSep($total)}"
echo &"Largest magic number: {insertSep($magicList[^1][^1])}"
echo "\nMagic number counts by number of digits:"
for length in 1..magicList.high:
echo &"{length:2}: {magicList[length].len}"
echo()
stdout.write "Minimally pandigital 1-9 magic numbers: "
for n in magicList[9]:
if n.isMinimallyPandigital('1'):
stdout.write insertSep($n), ' '
echo()
stdout.write "Minimally pandigital 0-9 magic numbers: "
for n in magicList[10]:
if n.isMinimallyPandigital('0'):
stdout.write insertSep($n), ' '
echo()
- Output:
Number of magic numbers: 20_457 Largest magic number: 3_608_528_850_368_400_786_036_725 Magic number counts by number of digits: 1: 10 2: 45 3: 150 4: 375 5: 750 6: 1200 7: 1713 8: 2227 9: 2492 10: 2492 11: 2225 12: 2041 13: 1575 14: 1132 15: 770 16: 571 17: 335 18: 180 19: 90 20: 44 21: 18 22: 12 23: 6 24: 3 25: 1 Minimally pandigital 1-9 magic numbers: 381_654_729 Minimally pandigital 0-9 magic numbers: 3_816_547_290
Pascal
Free Pascal
Only Using UInt64. Therefore 18 digits are the limit.
program MagicNUmbers;
{$IFDEF FPC}{$MODE DELPHI}{$Optimization ON,All}{$ENDIF}
{$IFDEF Windows}{$APPTYPE CONSOLE}{$ENDIF}
uses
sysutils;// TDatetime
const
CntMagicNUmbers = 2492;
var
MagicNumbs : array[0..CntMagicNUmbers] of Uint64;
MagicCnt : Int32;
function checkpanX_9(MinDigit : Int32):UInt64;
var
n,q : Uint64;
idx: Uint32;
testDigits,
AllDigits : set of 0..9;
begin
AllDigits := [];
For idx := 9 downto MinDigit do
include(AllDigits,idx);
For idx := 1 to MagicCnt do
begin
n := MagicNumbs[idx];
testDigits := [];
repeat
q := n DIV 10;
include(TestDigits,n-10*q);
n:= q;
until q = 0;
if TestDigits = AllDigits then
EXIT(MagicNumbs[idx]);
end;
end;
function ExtendMagic(dgtcnt:Int32):Boolean;
var
newMg : Uint64;
i,j,k : Int32;
begin
i := 1;
j := CntMagicNUmbers-MagicCnt+1;
Move(MagicNumbs[i],MagicNumbs[j],SizeOf(MagicNumbs[0])*MagicCnt);
if dgtcnt = 2 then //Jump over zero
inc(j);
repeat
newMg := MagicNumbs[j]*10;
k := newMg MOD dgtcnt;
IF k > 0 then
k := dgtCnt-k;
newMg += k;
while k in [0..9] do
Begin
MagicNumbs[i] := newMg;
k += dgtCnt;
newMg +=dgtcnt;
inc(i);
end;
inc(j);
until j > CntMagicNUmbers;
MagicCnt := i-1;
result := true;
end;
var
PAN1_9,PAN0_9: Int64;
i,sum : Int32;
Begin
MagicNumbs[1] := 0;
MagicCnt := 0;
sum := 0;
writeln('Magic number counts by number of digits and max value: ');
For i := 1 to 18 do
begin
ExtendMagic(i);
IF i = 9 then
PAN1_9 := checkpanX_9(1);
IF i = 10 then
PAN0_9 := checkpanX_9(0);
inc(sum,MagicCnt);
writeln(i:4,MagicCnt:10,MagicNumbs[MagicCnt]:19);
end;
Writeln(' Sum of MagicCnt: ',sum);
Writeln(' Pandigital number with 1..9: ', PAN1_9);
Writeln(' Pandigital number with 0..9: ', PAN0_9);
end.
- @TIO.RUN:
Magic number counts by number of digits and max value: 1 10 9 2 45 98 3 150 987 4 375 9876 5 750 98765 6 1200 987654 7 1713 9876545 8 2227 98765456 9 2492 987654564 10 2492 9876545640 11 2225 98765456405 12 2041 987606963096 13 1575 9876069630960 14 1132 98760696309604 15 770 987606963096045 16 571 9876062430364208 17 335 98485872309636009 18 180 984450645096105672 Sum of MagicCnt: 20283 Pandigital number with 1..9: 381654729 Pandigital number with 0..9: 3816547290
Perl
use strict;
use warnings;
use bigint;
my $dcnt = 1;
my @ok = my @magic = 0..9; shift @ok;
while () {
$dcnt++;
my @candidates = ();
for my $d (0..9) { push @candidates, map { 10*$_ + $d } @ok }
(@ok = grep { 0 == $_ % $dcnt } @candidates) ? push(@magic, @ok) : last;
}
printf "There are %d magic numbers in total.\nThe largest is %s.\n\n", scalar(@magic), $magic[-1];
my %M; $M{length $_}++ for @magic;
for my $k (sort { $a <=> $b } keys %M) {
printf " %6d with %3d digit%s\n", $M{$k}, $k, $k>1?'s':'';
}
for my $i (1,0) {
my $digits = join '', $i..9;
printf "\nMagic number(s) pan-digital in $i through 9 with no repeats: %s\n",
grep { length $_ == 10-$i and $digits eq join '', sort split '', $_ } @magic;
}
- Output:
There are 20457 magic numbers in total. The largest is 3608528850368400786036725. 10 with 1 digit 45 with 2 digits 150 with 3 digits 375 with 4 digits 750 with 5 digits 1200 with 6 digits 1713 with 7 digits 2227 with 8 digits 2492 with 9 digits 2492 with 10 digits 2225 with 11 digits 2041 with 12 digits 1575 with 13 digits 1132 with 14 digits 770 with 15 digits 571 with 16 digits 335 with 17 digits 180 with 18 digits 90 with 19 digits 44 with 20 digits 18 with 21 digits 12 with 22 digits 6 with 23 digits 3 with 24 digits 1 with 25 digits Magic number(s) pan-digital in 1 through 9 with no repeats: 381654729 Magic number(s) pan-digital in 0 through 9 with no repeats: 3816547290
Phix
Using strings
with javascript_semantics
function polydivisible()
sequence res = {}, prev = {""}, next = {}
integer digits = 1
while length(prev) do
for np in prev do
for d='0'+(digits=1) to '9' do
string n = np&d
integer rem = 0
for nd in n do
rem = remainder(rem*10+nd-'0',digits)
end for
if rem=0 then
next = append(next,n)
end if
end for
end for
if length(next) then
res = append(res,next)
end if
prev = next
next = {}
digits += 1
end while
res[1] = {"0"} & res[1]
return res
end function
sequence r = polydivisible(),
rc = apply(r,length)
string fmt = """
There are %,d magic numbers in total.
The largest is %s.
There are:
"""
printf(1,fmt,{sum(rc),r[$][$]})
for i,c in rc do
printf(1,"%,5d with %2d digit%s, the largest being %s\n",
{c,i,iff(i=1?"":"s"),r[i][$]})
end for
function pandigital(string s,p) return sort(s)=p end function
function evenonly(string s) return sum(apply(s,odd))=0 end function
function filter_even(sequence ri) return filter(ri,evenonly) end function
function palindromic(string s) return s=reverse(s) end function
function filter_pal(sequence ri) return filter(ri,palindromic) end function
string p1 = join(filter(r[9],pandigital,"123456789"),"\n"),
p0 = join(filter(r[10],pandigital,"0123456789"),"\n"),
evenpd = trim_tail(apply(r,filter_even),{{}})[$][$],
pallypd = trim_tail(apply(r,filter_pal),{{}})[$][$]
fmt = """%s
All magic numbers that are pan-digital in 1 through 9 with no repeats:
%s
All magic numbers that are pan-digital in 0 through 9 with no repeats:
%s
The longest polydivisible number that only uses even digits is:
%s
The longest palindromic polydivisible number is:
%s
"""
printf(1,fmt,{"\n",p1,p0,evenpd,pallypd})
- Output:
There are 20,457 magic numbers in total. The largest is 3608528850368400786036725. There are: 10 with 1 digit, the largest being 9 45 with 2 digits, the largest being 98 150 with 3 digits, the largest being 987 375 with 4 digits, the largest being 9876 750 with 5 digits, the largest being 98765 1,200 with 6 digits, the largest being 987654 1,713 with 7 digits, the largest being 9876545 2,227 with 8 digits, the largest being 98765456 2,492 with 9 digits, the largest being 987654564 2,492 with 10 digits, the largest being 9876545640 2,225 with 11 digits, the largest being 98765456405 2,041 with 12 digits, the largest being 987606963096 1,575 with 13 digits, the largest being 9876069630960 1,132 with 14 digits, the largest being 98760696309604 770 with 15 digits, the largest being 987606963096045 571 with 16 digits, the largest being 9876062430364208 335 with 17 digits, the largest being 98485872309636009 180 with 18 digits, the largest being 984450645096105672 90 with 19 digits, the largest being 9812523240364656789 44 with 20 digits, the largest being 96685896604836004260 18 with 21 digits, the largest being 966858966048360042609 12 with 22 digits, the largest being 9668589660483600426096 6 with 23 digits, the largest being 72645656402410567240820 3 with 24 digits, the largest being 402852168072900828009216 1 with 25 digits, the largest being 3608528850368400786036725 All magic numbers that are pan-digital in 1 through 9 with no repeats: 381654729 All magic numbers that are pan-digital in 0 through 9 with no repeats: 3816547290 The longest polydivisible number that only uses even digits is: 48000688208466084040 The longest palindromic polydivisible number is: 30000600003
Python
from itertools import groupby
def magic_numbers(base):
hist = []
n = l = i = 0
while True:
l += 1
hist.extend((n + digit, l) for digit in range(-n % l, base, l))
i += 1
if i == len(hist):
return hist
n, l = hist[i]
n *= base
mn = magic_numbers(10)
print("found", len(mn), "magic numbers")
print("the largest one is", mn[-1][0])
print("count by number of digits:")
print(*(f"{l}:{sum(1 for _ in g)}" for l, g in groupby(l for _, l in mn)))
print(end="minimally pandigital in 1..9: ")
print(*(m for m, l in mn if l == 9 == len(set(str(m)) - {"0"})))
print(end="minimally pandigital in 0..9: ")
print(*(m for m, l in mn if l == 10 == len(set(str(m)))))
- Output:
found 20457 magic numbers the largest one is 3608528850368400786036725 count by number of digits: 1:10 2:45 3:150 4:375 5:750 6:1200 7:1713 8:2227 9:2492 10:2492 11:2225 12:2041 13:1575 14:1132 15:770 16:571 17:335 18:180 19:90 20:44 21:18 22:12 23:6 24:3 25:1 minimally pandigital in 1..9: 381654729 minimally pandigital in 0..9: 3816547290
Raku
my \Δ = $ = 1;
my @magic = flat 0, [1..9], {last if .not; ++Δ; [(.flat X~ 0..9).grep: * %% Δ]}…*;
put "There are {@magic.eager.elems} magic numbers in total.";
put "\nThe largest is {@magic.tail}.";
put "\nThere are:";
put "{(+.value).fmt: "%4d"} with {.key.fmt: "%2d"} digit{1 == +.key ?? '' !! 's'}"
for sort @magic.classify: {.chars};
{
my $pan-digital = ($_..9).join.comb.Bag;
put "\nAll magic numbers that are pan-digital in $_ through 9 with no repeats: " ~
@magic.grep( { .comb.Bag eqv $pan-digital } );
} for 1, 0;
- Output:
There are 20457 magic numbers in total. The largest is 3608528850368400786036725. There are: 10 with 1 digit 45 with 2 digits 150 with 3 digits 375 with 4 digits 750 with 5 digits 1200 with 6 digits 1713 with 7 digits 2227 with 8 digits 2492 with 9 digits 2492 with 10 digits 2225 with 11 digits 2041 with 12 digits 1575 with 13 digits 1132 with 14 digits 770 with 15 digits 571 with 16 digits 335 with 17 digits 180 with 18 digits 90 with 19 digits 44 with 20 digits 18 with 21 digits 12 with 22 digits 6 with 23 digits 3 with 24 digits 1 with 25 digits All magic numbers that are pan-digital in 1 through 9 with no repeats: 381654729 All magic numbers that are pan-digital in 0 through 9 with no repeats: 3816547290
Rust
fn get_digits(mut n: u128) -> [usize; 10] {
let mut digits = [0; 10];
while n > 0 {
digits[(n % 10) as usize] += 1;
n /= 10;
}
digits
}
fn magic_numbers() -> impl std::iter::Iterator<Item = u128> {
let mut magic: Vec<u128> = vec![0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
let mut index = 0;
let mut digits = 2;
std::iter::from_fn(move || {
if index == magic.len() {
let mut magic_new: Vec<u128> = Vec::new();
for &m in &magic {
if m == 0 {
continue;
}
let mut n = 10 * m;
for _ in 0..10 {
if n % digits == 0 {
magic_new.push(n);
}
n += 1;
}
}
index = 0;
digits += 1;
magic = magic_new;
}
if magic.is_empty() {
return None;
}
let m = magic[index];
index += 1;
Some(m)
})
}
fn main() {
let mut count = 0;
let mut dcount = 0;
let mut magic: u128 = 0;
let mut p: u128 = 10;
let digits0 = [1; 10];
let digits1 = [0, 1, 1, 1, 1, 1, 1, 1, 1, 1];
let mut pandigital0: Vec<u128> = Vec::new();
let mut pandigital1: Vec<u128> = Vec::new();
let mut digit_count: Vec<usize> = Vec::new();
for m in magic_numbers() {
magic = m;
if magic >= p {
p *= 10;
digit_count.push(dcount);
dcount = 0;
}
let digits = get_digits(magic);
if digits == digits0 {
pandigital0.push(magic);
} else if digits == digits1 {
pandigital1.push(magic);
}
count += 1;
dcount += 1;
}
digit_count.push(dcount);
println!("There are {} magic numbers.\n", count);
println!("The largest magic number is {}.\n", magic);
println!("Magic number count by digits:");
for (i, c) in digit_count.iter().enumerate() {
println!("{}\t{}", i + 1, c);
}
println!("\nMagic numbers that are minimally pandigital in 1-9:");
for m in pandigital1 {
println!("{}", m);
}
println!("\nMagic numbers that are minimally pandigital in 0-9:");
for m in pandigital0 {
println!("{}", m);
}
}
- Output:
There are 20457 magic numbers. The largest magic number is 3608528850368400786036725. Magic number count by digits: 1 10 2 45 3 150 4 375 5 750 6 1200 7 1713 8 2227 9 2492 10 2492 11 2225 12 2041 13 1575 14 1132 15 770 16 571 17 335 18 180 19 90 20 44 21 18 22 12 23 6 24 3 25 1 Magic numbers that are minimally pandigital in 1-9: 381654729 Magic numbers that are minimally pandigital in 0-9: 3816547290
Wren
This is based on the Python code in the Wikipedia article.
import "./big" for BigInt
import "./fmt" for Fmt
var polydivisible = Fn.new {
var numbers = []
var previous = (1..9).toList
var new = []
var digits = 2
while (previous.count > 0) {
numbers.add(previous)
for (n in previous) {
for (j in 0..9) {
var number = BigInt.ten * n + j
if (number % digits == 0) new.add(number)
}
}
previous = new
new = []
digits = digits + 1
}
return numbers
}
var numbers = polydivisible.call()
numbers[0].add(BigInt.zero) // include zero
var total = numbers.reduce(0) { |acc, number| acc + number.count }
Fmt.print("There are $,d magic numbers in total.", total)
var largest = numbers[-1][-1]
Fmt.print("\nThe largest is $,i.", largest)
System.print("\nThere are:")
for (i in 0...numbers.count) {
Fmt.print("$,5d with $2d digit$s", numbers[i].count, i+1, (i == 0) ? "" : "s")
}
var pd19 = []
for (n in numbers[8]) {
var s = n.toString
var pandigital = true
for (i in 1..9) {
if (!s.contains(i.toString)) {
pandigital = false
break
}
}
if (pandigital) pd19.add(n)
}
System.print("\nAll magic numbers that are pan-digital in 1 through 9 with no repeats: ")
Fmt.print("$,i", pd19)
var pd09 = []
for (n in numbers[9]) {
var s = n.toString
var pandigital = true
for (i in 0..9) {
if (!s.contains(i.toString)) {
pandigital = false
break
}
}
if (pandigital) pd09.add(n)
}
System.print("\nAll magic numbers that are pan-digital in 0 through 9 with no repeats: ")
Fmt.print("$,i", pd09)
- Output:
There are 20,457 magic numbers in total. The largest is 3,608,528,850,368,400,786,036,725. There are: 10 with 1 digit 45 with 2 digits 150 with 3 digits 375 with 4 digits 750 with 5 digits 1,200 with 6 digits 1,713 with 7 digits 2,227 with 8 digits 2,492 with 9 digits 2,492 with 10 digits 2,225 with 11 digits 2,041 with 12 digits 1,575 with 13 digits 1,132 with 14 digits 770 with 15 digits 571 with 16 digits 335 with 17 digits 180 with 18 digits 90 with 19 digits 44 with 20 digits 18 with 21 digits 12 with 22 digits 6 with 23 digits 3 with 24 digits 1 with 25 digits All magic numbers that are pan-digital in 1 through 9 with no repeats: 381,654,729 All magic numbers that are pan-digital in 0 through 9 with no repeats: 3,816,547,290