%I A149246
%S A149246 1,1,4,11,38,116,440,1453,5450,18714,71816,253494,972292,3492890,13529192,
               49328285,191161466,
%T A149246 703792642,2742710728,10191899732,39738557836,148580923814,581445525832,
               2187826760962,
%U A149246 8565364278692,32366865951050,127044352702056,482288980929490,1893726046847320
%N A149246 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), 
               (1, 0, -1), (1, 1, 1)}
%H A149246 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 A149246 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[-1 
               + i, 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 A149246 Sequence in context: A017939 A130494 A027573 this_sequence A149247 A149248 
               A149249
%Y A149246 Adjacent sequences: A149243 A149244 A149245 this_sequence A149247 A149248 
               A149249
%K A149246 nonn,walk
%O A149246 0,3
%A A149246 Manuel Kauers (manuel(AT)kauers.de), Nov 18 2008