- var_dump: documentation ( source)
- mt_rand: documentation ( source)
- array_keys: documentation ( source)
<?php
$numberOfRandoms = 500;
$uniques = array();
do {
$uniques[mt_rand(10000, 99999)] = true;
} while(count(array_keys($uniques)) < 500);
$uniques = array_keys($uniques);
var_dump($uniques);