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A151230 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), (0, 1, -1), (1, 0, 1), (1, 1, 0), (1, 1, 1)} 0
1, 3, 13, 59, 276, 1326, 6430, 31466, 154803, 764468, 3786401, 18790430, 93402254, 464815171, 2315297901, 11541079787, 57561303467, 287218778948, 1433675907696, 7158410796594, 35750733174914, 178581809177037, 892192055382607, 4457958395036094, 22277194997673579, 111332957862488865 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..25.

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[-1 + i, -1 + j, k, -1 + n] + aux[-1 + i, j, -1 + k, -1 + n] + aux[i, -1 + j, 1 + 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: A262664 A151229 A333472 * A151231 A299502 A151321

Adjacent sequences:  A151227 A151228 A151229 * A151231 A151232 A151233

KEYWORD

nonn,walk

AUTHOR

Manuel Kauers, Nov 18 2008

STATUS

approved

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Last modified September 20 13:19 EDT 2020. Contains 337264 sequences. (Running on oeis4.)