$re = '/(?:(?=0[1-9]|1[2-9]|2[3-9]|3[4-9]|4[5-9]|5[6-9]|6[7-9]|7[8-9]|89)\d)+\d/';
$str = '5136789431235';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php