Chernick's Carmichael numbers: Difference between revisions
→{{header|Perl 6}}: Add a Perl 6 example
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a(8) = 53487697914261966820654105730041031613370337776541835775672321
a(9) = 58571442634534443082821160508299574798027946748324125518533225605795841
</pre>
=={{header|Perl 6}}==
{{works with|Rakudo|2019.03}}
{{trans|Perl}}
Use the ntheory library from Perl 5 for primality testing since it is much, ''much'' faster than Perl 6s built-in .is-prime method.
<lang perl6>use Inline::Perl5;
use ntheory:from<Perl5> <:all>;
sub chernick-carmichael-factors ($n, $m) {
6*$m + 1, 12*$m + 1, |((1 .. $n-2).map: { (1 +< $_) * 9*$m + 1 } )
}
sub chernick-carmichael-number ($n) {
my $multiplier = 1;
my $iterator = 1 .. *;
if $n > 4 {
$multiplier = 1 +< ($n-4);
$iterator = (1..*).map: * * 5;
}
my $i = $iterator.first: -> $m {
next unless [&&] chernick-carmichael-factors($n, $m * $multiplier).map: { is_prime($_) #`[ .is-prime ] };
last
}
chernick-carmichael-factors($n, $i * $multiplier);
}
for 3 .. 9 -> $n {
my @f = chernick-carmichael-number($n);
say "a($n): {[*] @f} = {@f.join(' ⨉ ')}";
}</lang>
{{out}}
<pre>a(3): 1729 = 7 ⨉ 13 ⨉ 19
a(4): 63973 = 7 ⨉ 13 ⨉ 19 ⨉ 37
a(5): 26641259752490421121 = 2281 ⨉ 4561 ⨉ 6841 ⨉ 13681 ⨉ 27361
a(6): 1457836374916028334162241 = 2281 ⨉ 4561 ⨉ 6841 ⨉ 13681 ⨉ 27361 ⨉ 54721
a(7): 24541683183872873851606952966798288052977151461406721 = 4681921 ⨉ 9363841 ⨉ 14045761 ⨉ 28091521 ⨉ 56183041 ⨉ 112366081 ⨉ 224732161
a(8): 53487697914261966820654105730041031613370337776541835775672321 = 5703361 ⨉ 11406721 ⨉ 17110081 ⨉ 34220161 ⨉ 68440321 ⨉ 136880641 ⨉ 273761281 ⨉ 547522561
a(9): 58571442634534443082821160508299574798027946748324125518533225605795841 = 5703361 ⨉ 11406721 ⨉ 17110081 ⨉ 34220161 ⨉ 68440321 ⨉ 136880641 ⨉ 273761281 ⨉ 547522561 ⨉ 1095045121
</pre>
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