The Collatz Conjecture states that for any natural number n, if n is even, divide it by 2. If n is odd, multiply it by 3 and add 1. If you repeat the process continously for n, n will eventually reach 1.

gistfile1.txt

function collatz(n){
var i = 0, c = [];
c.push(n);

while (c[i] > 1) {
  if (c[i] % 2 == 0) {
    c.push(c[i] / 2);
    }
  else if (Math.abs(c[i] % 2) == 1) {
    c[i] = (c[i] * 3) + 1;
    c.push(c[i]);
    }
    i++ ;
    }
  return c.length;
}