<?php
  $gen_string = '';
  $gen_string_first = '000000000';
  $gen_string_last = '000000500';
  $gen_string_final = '';
  //set_time_limit(0);
  function str_compare($digit) {
    $compare_string = '121212121';
    $string = '';
    for ($i = '0'; $i <= '8'; $i++) {
      if ($digit{$i} * $compare_string{$i} >= '10') {
        $ii = $digit{$i} * $compare_string{$i};
        settype($ii, "string");
        $string .= $ii{0} + $ii{1};
      }
      else {
        $string .= $digit{$i} * $compare_string{$i};
      }
    }
    return $string;
  }
  function str_validate($string) {
    settype($string, "string");
    $string = $string{0} + $string{1} + $string{2} + $string{3} + $string{4} + $string{5} + $string{6} + $string{7} + $string{8};
    if (preg_match("/^[0-9][0]$/", $string)) {
      return true;
    }
    else {
      return false;
    }
  }
  for ($gen_string = $gen_string_first; $gen_string <= $gen_string_last; $gen_string++) {
    if (strlen($gen_string) <= '1') { $gen_string = '00000000' . $gen_string; }
    elseif (strlen($gen_string) <= '2') { $gen_string = '0000000' . $gen_string; }
    elseif (strlen($gen_string) <= '3') { $gen_string = '000000' . $gen_string; }
    elseif (strlen($gen_string) <= '4') { $gen_string = '00000' . $gen_string; }
    elseif (strlen($gen_string) <= '5') { $gen_string = '0000' . $gen_string; }
    elseif (strlen($gen_string) <= '6') { $gen_string = '000' . $gen_string; }
    elseif (strlen($gen_string) <= '7') { $gen_string = '00' . $gen_string; }
    elseif (strlen($gen_string) <= '8') { $gen_string = '0' . $gen_string; }
    elseif (strlen($gen_string) <= '9') { $gen_string = $gen_string;}
    else { die('Too many values returned. Caustringg an error!'); }
    settype($gen_string, "string");
    if (str_validate(str_compare($gen_string)) == true) {
      echo $gen_string . "\n";
    }
  }
?>