A note on the enumeration of diffusion walks in the first octant by their number of contacts with the diagonal
J. Integer Seq. 8(4), Article 05.4.3, 7 p., electronic only (2005)
Summary
Summary: Diffusion walks take steps in the four directions N, E, S, and W. We derive a closed form for the number of diffusion walks from the origin to some point $(n,n)$ on the diagonal in $k$ steps inside the first octant, touching the diagonal exactly $c$ times.
