I try my best at Project Euler. Both fun and highly challenging.

Problem 12 reads Which is the first triangle number to have over five-hundred divisors?

I also play with PE and this is what I had used:

#!/usr/bin/perl -l

use strict;
use warnings;

my $n;
my @div=(0);

while (++$n) {
    my ($m,$p)=($n,0);
    $m /= 2 and $p++ until $m & 1;
    $div[$n] = $p ?
      $div[$m]*$p :
      grep !($n%$_), 1..$n;
    print $n*($n-1)/2 and last
      if $div[$n]*$div[$n-1] > 500;
}

__END__
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