%I A149120
%S A149120 1,1,4,9,32,103,361,1307,4792,18033,68631,265451,1034256,4083197,16204618,
               64889975,261337858,
%T A149120 1058251013,4309632977,17616277293,72364546556,298151009423,1233408725210,
               5115914210353,
%U A149120 21288345954796,88803907834511,371383647629043,1556761843796677,6538881650516046
%N A149120 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, 0), (-1, 0, 0), 
               (0, -1, 1), (1, -1, -1), (1, 1, 0)}
%H A149120 A. Bostan and M. Kauers, 2008. Automatic Classification of Restricted 
               Lattice Walks, <a href="http://arxiv.org/abs/0811.2899">ArXiv 0811.2899</
               a>.
%t A149120 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, k, -1 + n] + aux[-1 + 
               i, 1 + j, 1 + k, -1 + n] + aux[i, 1 + j, -1 + k, -1 + n] + aux[1 
               + i, j, k, -1 + n] + aux[1 + i, 1 + j, k, -1 + n]]; Table[Sum[aux[i, 
               j, k, n], {i, 0, n}, {j, 0, n}, {k, 0, n}], {n, 0, 10}]
%Y A149120 Sequence in context: A149117 A149118 A149119 this_sequence A057819 A129196 
               A119574
%Y A149120 Adjacent sequences: A149117 A149118 A149119 this_sequence A149121 A149122 
               A149123
%K A149120 nonn,walk
%O A149120 0,3
%A A149120 Manuel Kauers (manuel(AT)kauers.de), Nov 18 2008