#!/usr/local/bin/perl -wl
use strict;

my ($prime, $max) = (2, shift || 50);          # First prime, max number.
my @sieve = (0, 0, map {1;} ($prime .. $max)); # Init sieve.

while ((my $product = $prime * $prime) <= $max) {
  do {$sieve [$product] = 0;} 
    while (($product += $prime) <= $max);
  do {$prime ++;}
    while !$sieve [$prime];
}

map {print if $sieve [$_];} (0 .. $max);