%I A150567
%S A150567 1,2,7,26,107,457,2016,9065,41424,191529,894019,4204565,19897098,94641154,
               452107980,2167676408,
%T A150567 10425903303,50282484818,243082789531,1177611502760,5715528217575,27786221354972,
%U A150567 135284133335976,659545295681644,3219346412950448,15731435487175994,76949340577947377
%N A150567 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, 0, 0), (0, 0, 1), (1, 
               -1, 1), (1, 0, 1), (1, 1, -1)}
%H A150567 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 A150567 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, 1 + j, -1 + k, -1 + n] + aux[i, 
               j, -1 + k, -1 + n] + aux[1 + i, j, k, -1 + n]]; Table[Sum[aux[i, 
               j, k, n], {i, 0, n}, {j, 0, n}, {k, 0, n}], {n, 0, 10}]
%Y A150567 Sequence in context: A150564 A150565 A150566 this_sequence A000151 A150568 
               A102319
%Y A150567 Adjacent sequences: A150564 A150565 A150566 this_sequence A150568 A150569 
               A150570
%K A150567 nonn,walk
%O A150567 0,2
%A A150567 Manuel Kauers (manuel(AT)kauers.de), Nov 18 2008