Someone

<?
$stime = microtime(true);

$i = 8;
$j = 0;
$cont = true;

$list = "2, 3, 5, 7";

while($i < 500){
  $somevar = explode(", ",$list);
  if(($i % 2 != 0) && ($i % 3 != 0) && ($i % 5 != 0) && ($i % 7 != 0)){
    while(($somevar[$j] <= sqrt($i)) && ($cont)){
      if($i % $somevar[$j] == 0){
        $cont = false;
      }
      $j++;
    }
    if($cont){
      $list .= ", $i";
    }
    $j = 0;
  }
  $i++;
  $cont = true;
}

echo $list."\n\n";

printf("%01.5f",microtime(true)-$stime);
?>