Hi kt5016; Your formula is indeed correct for (0,0,0) to (m,m,m). It exactly coincides with the number of paths of length 3n in an m x m x m grid from (0,0,0) to (m,m,m) and is called De Bruijn's s(3,n). Your fomula for (0,0,0) to (m,m,m) becomes \Large {3m \choose m } { 2m \choose m } {m \choose m ...