Explosive Sum

gistfile1.js

var sum = function(number){
	return p(number, number);
}
var memo = [];
var p = function (n, m){
	if (m == 0 ) { return 0;};
	if (n == 0) { return 1};
	if (n < 0) { return 0};
	if (memo[n] == undefined) memo[n] = [];
	var result = memo[n][m];
	if (typeof result != 'number') {
		result = p(n-m, m) + p(n, m-1);
		memo[n][m] = result;
	};
	return result;
};