# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a148157 Showing 1-1 of 1 %I A148157 #4 Dec 28 2023 19:45:38 %S A148157 1,1,2,4,11,30,96,303,1029,3503,12545,45113,167408,623906,2378074, %T A148157 9109462,35460401,138679512,548909493,2182414131,8757633284, %U A148157 35287783051,143225649827,583526061368,2391378062528,9833988357144,40635483278352,168436746650379,701005791862862,2925735406975962 %N A148157 Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (-1, 0, 1), (0, 0, 1), (0, 1, -1), (1, -1, 1)}. %H A148157 A. Bostan and M. Kauers, 2008. Automatic Classification of Restricted Lattice Walks, ArXiv 0811.2899. %t A148157 aux[i_Integer, j_Integer, k_Integer, n_Integer] := Which[Min[i, j, k, n] < 0 || Max[i, j, k] > n, 0, n == 0, KroneckerDelta[i, j, k, n], True, aux[i, j, k, n] = aux[-1 + i, 1 + j, -1 + k, -1 + n] + aux[i, -1 + j, 1 + k, -1 + n] + aux[i, j, -1 + k, -1 + n] + aux[1 + i, j, -1 + k, -1 + n] + aux[1 + i, 1 + j, -1 + k, -1 + n]]; Table[Sum[aux[i, j, k, n], {i, 0, n}, {j, 0, n}, {k, 0, n}], {n, 0, 10}] %K A148157 nonn,walk %O A148157 0,3 %A A148157 _Manuel Kauers_, Nov 18 2008 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE