the_0ne,
I understand that, which is why I said modifying the code would not be difficult to do that. The problem is you seem to want to proceed with using a technique that is producing far more candidates than is necessary. Making a terrible approach more efficient isn't going to make it work.

Cheers - L~R

Update: Even with only pulling unique combinations, it does not take long to get to astronimical numbers as pointed out by kvale earlier. Try out the following code.

#!/usr/bin/perl
use strict;
use warnings;

my $k = $ARGV[0] || 50;
my $total = 1;

for my $n ( 1 .. $k - 1 ) {
    if ( $n > $k - $n ) {
        $total += factorial($k, $n + 1) / factorial( $k - $n );
    }
    else {
        $total += factorial($k, $k - $n + 1) / factorial( $n );
    }
}
print "Total unique combinations for $k is $total\n";

sub factorial {
    my ($n, $max, $total) = @_;
    $total ||= 1;
    $max   ||= 0;
    return $total if ! $n || $n == $max - 1;
    @_ = ($n - 1, $max, $total * $n);
    goto &factorial;
}
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