Calculate Primes

// Fibonacci
// http://en.wikipedia.org/wiki/Fibonacci_number
var isPrime = function(n, arr) {
	for (var i = 0; i < arr.length; i++) {
		if (arr[i] > Math.sqrt(n)) {
			break;
		}
		if ((n % arr[i]) == 0) {
			return false;
		}
	}
	return true;
};

 // Fibonacci: closed form expression
 // http://en.wikipedia.org/wiki/Golden_ratio#Relationship_to_Fibonacci_sequence
var calculatePrime = function(arr) {
	if(arr.length == 0) {
		return [2];
	}
	var i = arr[arr.length - 1] + 1;
	while (!isPrime(i, arr)) {
		i = i + 1;
	}
	arr.push(i)
	return arr;
};

// Find first K Fibonacci numbers via basic for loop
var firstPrimeNumber = function(k) {
	var i = 1;
	var arr = [];
	while (arr.length < k) {
		arr = calculatePrime(arr);
	}
	return arr;
};

 // Print to console
 var fmt = function(arr) {
	return arr.join(",");
	//return arr;
 };

 var k = 100;
 //console.log("firstkfib(" + k + ")");
 //console.log(fmt(firstPrimeNumber(k)));
 var fs = require('fs');
 var outfile = "prime.txt";
 var out = fmt(firstPrimeNumber(k));
 fs.writeFileSync(outfile, out);  
 //console.log("Script: " + __filename + "\nWrote: " + out + "To: " + outfile);