The underlying concepts of UVa 371: Ackermann Functions  have been discussed in great details in our post of Collatz problem. In this post, we simply outlines an ad-hoc algorithm as a solution to this problem as follows. [gist]5162026[/gist]

Please leave a comment if you have any question regarding this problem or implementation. Thanks.

See Also

Collatz Problem a.k.a. 3n+1 Problem.

UVa 100. 3n+1 Problem.