3lettercode.php

<?php
  $i = 0;
    while ($i < 70){
      $s = substr(str_shuffle(str_repeat("abcdefghkmnpqrstuvwxyz", 3)), 0, 2);
      echo "a" . $s . "\r\n";
      $i++;
    }

   $j = 0;
    while ($j < 70){
      $t = substr(str_shuffle(str_repeat("abcdefghkmnpqrstuvwxyz", 3)), 0, 2);
      echo "b" . $t . "\r\n";
      $j++;
    }
?>