gistfile1.js

var async = require('async')
var final_array = [];

function a(param) {

	return function() { 
		param * 10;
	};

};

function b() {
	function c(callback){
		var arr = [];
		for (var i = 1; i <= 3; i++) {
			arr.push(a(i));
		};
		callback(null, arr);		
	};

	function d(arr, callback){
		console.log(arr[1]());
		callback();
	};

	async.waterfall([c, d]);
};

b();