for ( 1 .. 700000 ){ is_vamp( $_ ) and print $_,$/ } sub is_vamp { $_ = shift; my$l = (length( $_ ))/2; /(\d{$l})(\d{$l})/ or return; ((reverse$1)*$2 == $_) ? 1 : 0 } __END__ 1260 1435 1530 6880 102510 104260 105210 108135 152608 156240 182650 629680