Suppose you pick a random integer n. If it is even, divide the number by 2, if it is odd, multiply it by three and add 1 and repeat. People think that no matter what integer you pick, it will always end up oscillating between 4, 2, 1, 4, 2, 1, 4, 2, 1...But no one has proved it yet. I looked it up and came across this: http://en.wikipedia.org/wiki/Hailstone_sequence For fun I wrote a program to evaluate the hailstone sequence for any n you choose and uploaded it here: http://www.mediafire.com/?sharekey=f32833b26a7b8da667cd7f7bd65f7eefe04e75f6e8ebb871 You might check it out. I've tried probably a hundred different values of n and they all end up 4, 2, 1... Think it will ever be proved?