My prof was also more impressed by my implementing it than by my attempted proofs. (Not the first time this has happened!) I just implemented it too. I notic

My prof was also more impressed by my implementing it than by my attempted proofs. (Not the first time this has happened!) I just implemented it too. I notice that by 100K, you get an intermediate result of size just less than 2^31, but at 1M, you get an intermediate result of size about 2^36. Maybe I went up above 100K. For more: http://en.wikipedia.org/wiki/Collatz_conjecture#Experimental_evidence http://en.wikipedia.org/wiki/Collatz_conjecture#Experimental..., which includes some very nice plots, and a fractal construction when iterating an extension of the map to the complex plane. Whew! (On the other hand, https://xkcd.com/710/ https://xkcd.com/710/)