By Doron Zeilberger
(Exclusively published in the Personal Journal of Shalosh B. Ekhad and Doron Zeilberger)
Written: April 11, 2005.
Many humans fear and dislike recursive algorithms, but computers don't mind them, and I love them. In this particular case, a recursive formulation makes things very transparent and almost trivial. It also makes it very easy to program. In fact here is the very short Maple program .