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A149883 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, -1), (-1, -1, 0), (0, 0, 1), (0, 1, 0), (1, 1, -1)} 0
1, 2, 5, 14, 44, 147, 508, 1806, 6593, 24580, 93111, 357499, 1389352, 5456743, 21626045, 86391867, 347600899, 1407638294, 5733467909, 23475925302, 96585554635, 399129402469, 1656045861075, 6896872486071, 28822701485613, 120840949544465, 508153828762386, 2142852405007664, 9060003986577369 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..28.

A. Bostan and M. Kauers, 2008. Automatic Classification of Restricted Lattice Walks, ArXiv 0811.2899.

MATHEMATICA

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, 1 + j, k, -1 + n] + aux[1 + i, 1 + j, 1 + k, -1 + n]]; Table[Sum[aux[i, j, k, n], {i, 0, n}, {j, 0, n}, {k, 0, n}], {n, 0, 10}]

CROSSREFS

Sequence in context: A306799 A148335 A268419 * A307786 A149884 A149885

Adjacent sequences:  A149880 A149881 A149882 * A149884 A149885 A149886

KEYWORD

nonn,walk

AUTHOR

Manuel Kauers, Nov 18 2008

STATUS

approved

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Last modified June 25 22:13 EDT 2022. Contains 354868 sequences. (Running on oeis4.)