Converts the integer to binary and outputs list of integers that are power of 2 (http://jabran.me/using-special-integers-with-bitwise-operators-for-php-rbac/)

decimal2binary.php

<?php
/**
 * Converts the integer to binary and outputs list of integers that are power of 2
 * 
 * @author: Jabran Rafique <hello@jabran.me>
 * @param: integer $decimal
 * @return: string
 */

function get_special_binary( $decimal ) {
  $binaries = '';
  for ( $i = 1; $i < $decimal; $i++ ) {
  	$special_num = pow(2, $i);
  	$value = str_pad(base_convert($special_num, 10, 2), 8, '0', STR_PAD_LEFT);
  	$binaries .= sprintf('%s = %s %s <br />', $special_num, substr($value, 0, 4), substr($value, 4));
  }
  return $binaries;
}