var start = +new Date();
var gs = 20;
var f = [];
var paths = fact(2*gs)/Math.pow(fact(gs),2);
document.write("Euler #15 Javascript: "+paths+" Total Time: "+((+new Date() - start)/1000)+"sec
");
function fact(n){
	if(n==0||n==1) return 1;
	else if(f[n]>0) return f[n];
	else return f[n]=fact(n-1)*n;
}

	$gs = 20;
	$paths = nfact(2*$gs)/pow(nfact($gs),2);
	echo $paths;
	function nfact($n)
	{
	  if ($n == 0)
	  {
	    return 1;
	  }
	  else
	  {
	    return $n * nfact($n - 1);
	  }
	}