LCM method (using GCD through Euclid) to find the smallest number that can be divided with number 1 to 20

euclid.php

<?php
	/*
	* function gcd()
	* 
	* returns greatest common divisor
	* between two numbers
	* tested against gmp_gcd()
	* credit: http://php.net/manual/en/function.gmp-gcd.php#86931
	*/
	function gcd($a, $b)
	{
	    if ($a == 0 || $b == 0)
	        return abs( max(abs($a), abs($b)) );
	        
	    $r = $a % $b;
	    return ($r != 0) ?
	        gcd($b, $r) :
	        abs($b);
	}
	function lcm($num1, $num2)
	{
		$gcd = gcd($num1, $num2);
		return ($num1 * $num2) / $gcd;
	}
	$number = 1;
	$current = 1;
	for($i=1; $i<20; $i++)
	{
		$current = lcm($current, $number+1);
		$number++;
	}
	echo $current;
?>