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A151192 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, 0), (1, 1, 0), (1, 1, 1)} 0
1, 3, 12, 52, 235, 1101, 5220, 25095, 121545, 592284, 2899874, 14245601, 70184982, 346528860, 1714063397, 8490860344, 42111682813, 209073230631, 1038876078407, 5165898092581, 25703761512770, 127961411281276, 637325546777479, 3175535870819601, 15827934678897576, 78915817742970026 (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, 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: A125187 A151190 A151191 * A151193 A151194 A268208

Adjacent sequences:  A151189 A151190 A151191 * A151193 A151194 A151195

KEYWORD

nonn,walk

AUTHOR

Manuel Kauers, Nov 18 2008

STATUS

approved

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Last modified December 5 23:39 EST 2019. Contains 329784 sequences. (Running on oeis4.)