@article{BoChHoPe11, author = {Bostan, Alin and Chyzak, Fr\'ed\'eric and van Hoeij, Mark and Pech, Lucien}, title = {Explicit formula for the generating series of diagonal {3D} rook paths}, journal = {S\'eminaire Lotharingien de Combinatoire}, year = {2011}, volume = {B66a}, page = {27 pages}, url = {http://www.emis.de/journals/SLC/wpapers/s66bochhope.html}, abstract = {Let $a_n$ denote the number of ways in which a chess rook can move from a corner cell to the opposite corner cell of an $n \times n \times n$ three-dimensional chessboard, assuming that the piece moves closer to the goal cell at each step. We describe the computer-driven \emph{discovery and proof\/} of the fact that the generating series $G(x)= \sum_{n \geq 0} a_n x^n$ admits the following explicit expression in terms of a Gaussian hypergeometric function: \[ G(x) = 1 + 6 \cdot \int_0^x \frac{ \,\pFq21{1/3}{2/3}{2} {\frac{27 w(2-3w)}{(1-4w)^3}}}{(1-4w)(1-64w)} \, dw. \]}, }