[schmittz]

A slight typo in the author's bit (which is fascinating), the Collatz sequence doesn't terminate in a series of 1's. By its definition, once 1 is reached, the series repeats {1,4,2,1,4....}. Thus, the number of steps required to reach 1 is called the "stopping time" of the sequence. See the Wikipedia article on the Collatz conjecture for some great visualizations of low seed value termination trajectories for the Collatz sequence:

http://en.wikipedia.org/wiki/Collatz_conjecture