Jordan-Pólya numbers
Partial translation of Go
# 20230719 Raku programming solution
my \factorials = 1, | [\*] 1..18; # with 0!
sub JordanPolya (\limit) {
my \ix = (factorials.keys.first: factorials[*] >= limit) // factorials.end;
my ($k, @res) = 2, |factorials[0..ix];
while $k < @res.elems {
my \rk = @res[$k];
for 2 .. @res.elems -> \l {
my \kl = $ = @res[l] * rk;
last if kl > limit;
loop {
my \p = @res.keys.first: { @res[$_] >= kl } # performance
if p < @res.elems and @res[p] != kl {
@res.splice: p, 0, kl
} elsif p == @res.elems {
@res.append: kl
}
kl > limit/rk ?? ( last ) !! kl *= rk
}
}
$k++
}
return @res[1..*]
}
my @result = JordanPolya 2**30 ;
say "First 50 Jordan-Pólya numbers:";
say [~] $_>>.fmt('%5s') for @result[^50].rotor(10);
print "\nThe largest Jordan-Pólya number before 100 million: ";
say @result.first: * < 100_000_000, :end;
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