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xk/happyNumbers.js

Created February 10, 2014 23:40
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Concise Happy Numbers JavaScript
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happyNumbers.js
//2014-02-10 jorge@jorgechamorro.com concise happy numbers JavaScript
function happy (n) {
var past= [];
while (n= [].reduce.call(n.toString(), function (a,n) { return a+n*n }, 0))
if (n === 1) return 1; else if (past.indexOf(n) >= 0) return 0; else past.push(n);
}
for (var i=0 ; i<=100 ; ++i) happy(i) && console.log(i);
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