Project Euler Problem 92

by michiganfootball20

HTML

<div id="answer"></div>

JavaScript

$(document).ready(function () {
    numbers = [];
    numbers[1] = 1;
    numbers[89] = 89;

    function digit_chain(num) {
        if (numbers[num] !== undefined) return numbers[num];
        else {
            var str = num.toString();
            var sum = 0;
            for (var i = 0;i < str.length; i++) {
                sum += str[i] * str[i];
            }
            numbers[num] = digit_chain(sum);
            return numbers[num];
        }
    }

    count = 0;
    for(j = 1; j<100000; j++) {if(digit_chain(j) === 89) count++;}
    alert(count);

});