# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a151315 Showing 1-1 of 1 %I A151315 #4 Dec 04 2016 13:57:00 %S A151315 1,3,10,37,138,526,2030,7877,30782,120726,475008,1874068,7407446, %T A151315 29329716,116285466,461555291,1833766116,7291280658,29011041208, %U A151315 115498923044,460056287616,1833313414216,7308504710010,29145182257596,116260990142440,463889711899484,1851384051250070,7390399587090530 %N A151315 Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0) and consisting of n steps taken from {(-1, -1), (0, 1), (1, 0), (1, 1)} %H A151315 M. Bousquet-Mélou and M. Mishna, 2008. Walks with small steps in the quarter plane, ArXiv 0810.4387. %H A151315 A. Bostan and M. Kauers, 2008. Automatic Classification of Restricted Lattice Walks, ArXiv 0811.2899. %t A151315 aux[i_Integer, j_Integer, n_Integer] := Which[Min[i, j, n] < 0 || Max[i, j] > n, 0, n == 0, KroneckerDelta[i, j, n], True, aux[i, j, n] = aux[-1 + i, -1 + j, -1 + n] + aux[-1 + i, j, -1 + n] + aux[i, -1 + j, -1 + n] + aux[1 + i, 1 + j, -1 + n]]; Table[Sum[aux[i, j, n], {i, 0, n}, {j, 0, n}], {n, 0, 25}] %K A151315 nonn,walk %O A151315 0,2 %A A151315 _Manuel Kauers_, Nov 18 2008 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE