Wolstenholme numbers: Difference between revisions
Created Nim solution.
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(Created Nim solution.) |
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15: 40306783143871607599250..98658901192511859288941 (1539 digits)
</pre>
=={{header|Nim}}==
===Task===
Using only the standard library modules.
<syntaxhighlight lang="Nim">import std/rationals
func isPrime(n: Natural): bool =
if n < 2: return false
if (n and 1) == 0: return n == 2
if n mod 3 == 0: return n == 3
var k = 5
while k * k <= n:
if n mod k == 0 or n mod (k + 2) == 0: return false
inc k, 6
result = true
iterator wolstenholme(): (int, int) =
var count = 0
var k = 1
var s = 1.toRational
while true:
inc count
yield (count, s.num)
inc k
s += 1 // (k * k)
echo "First 20 Wolstenholme numbers:"
var wprimes: seq[int]
for (count, n) in wolstenholme():
echo n
if n.isPrime:
wprimes.add n
if count == 20: break
echo "\nFirst 4 Wolstenholme primes:"
for i in 0..3:
echo wprimes[i]
</syntaxhighlight>
{{out}}
<pre>First 20 Wolstenholme numbers:
1
5
49
205
5269
5369
266681
1077749
9778141
1968329
239437889
240505109
40799043101
40931552621
205234915681
822968714749
238357395880861
238820721143261
86364397717734821
17299975731542641
First 4 Wolstenholme primes:
5
266681
40799043101
86364397717734821</pre>
===Stretch task===
{{libheader|bignum}}
<syntaxhighlight lang="Nim">import std/strformat
import bignum
iterator wolstenholme(): (int, Int) =
var count = 0
var k = 1
var s = newRat(1)
while true:
inc count
yield (count, s.num)
inc k
s += newRat(1, k * k)
var wprimes: seq[Int]
for (count, n) in wolstenholme():
if wprimes.len < 15 and probablyPrime(n, 25) != 0:
wprimes.add n
if count in [500, 1000, 2500, 5000, 10000]:
echo &"The {count}th Wolstenholme number has {len($n)} digits."
if count == 10000: break
echo "\nDigit count of the first 15 Wolstenholme primes:"
for i in 0..14:
echo &"{i + 1: >2}: {len($wprimes[i])}"
</syntaxhighlight>
{{out}}
<pre>The 500th Wolstenholme number has 434 digits.
The 1000th Wolstenholme number has 866 digits.
The 2500th Wolstenholme number has 2164 digits.
The 5000th Wolstenholme number has 4340 digits.
The 10000th Wolstenholme number has 8693 digits.
Digit count of the first 15 Wolstenholme primes:
1: 1
2: 6
3: 11
4: 17
5: 104
6: 156
7: 218
8: 318
9: 520
10: 649
11: 935
12: 984
13: 1202
14: 1518
15: 1539</pre>
=={{header|Perl}}==
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