use strict; use warnings; sub sifter { my $p = shift; my $c = $p; return sub { $c += $p while $c < $_[0]; return $c-$_[0]; } } my @sieves; my $n = 1; loop: while( $n++ ){ $_->( $n ) or next loop for @sieves; push @sieves, sifter( $n ); print "$n\n"; }