It took me a solid 10 Minutes to parse the logic of that inner block. In german we have an expression for that: Von hinten durch die Brust ins Auge. Consider the following code, I think it makes the intention much clearer and it doesn't use globals.

use Modern::Perl;
use Sub::Signatures;
use ntheory 'primes';
use bigint;

print join "*", sieve3( 12, 1, 10, 10, 100 );

sub sieve3 ( $n, $c, $k, $l, $p )
{
    my %candidates = map { $_ => $n * ( $k + $_ ) + $c } ( 0 .. $l );
    
    foreach my $prime ( @{primes $p} )
    {
        foreach my $candidate ( keys %candidates )
        {
            delete $candidates{$candidate}
                if defined $candidates{$candidate} && $candidates{$can
+didate} % $prime == 0;
        }
    }
    
    return sort { $a <=> $b } keys %candidates;
}
[download]