%I A149815
%S A149815 1,2,4,10,26,76,248,796,2654,8942,30952,112110,403446,1474050,5415092,
               20126040,76723180,
%T A149815 291325720,1115293334,4283685580,16561655330,65111198066,255211841296,
               1005521776936,
%U A149815 3970064457452,15742010094734,63185813520174,252973809922464,1016451149145374,
               4089942429478792
%N A149815 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, -1), 
               (0, 0, 1), (0, 1, 0), (1, -1, -1)}
%H A149815 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 A149815 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, k, -1 + n] + aux[i, j, -1 + k, -1 + n] + aux[1 + i, j, 1 
               + 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 A149815 Sequence in context: A000085 A047653 A148100 this_sequence A149816 A149817 
               A149818
%Y A149815 Adjacent sequences: A149812 A149813 A149814 this_sequence A149816 A149817 
               A149818
%K A149815 nonn,walk
%O A149815 0,2
%A A149815 Manuel Kauers (manuel(AT)kauers.de), Nov 18 2008