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A148522 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, -1), (1, -1, 0), (1, 1, 0)} 0
1, 1, 3, 5, 17, 40, 139, 365, 1321, 3796, 13865, 41676, 155184, 487528, 1823899, 5870889, 22212061, 73415388, 278531017, 934712928, 3572512184, 12202646184, 46722602013, 161264038912, 620704085796, 2169656200496, 8361338551912, 29449934951492, 113937676300992, 405143448826160, 1568854152864327 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..30.

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, k, -1 + n] + aux[-1 + i, 1 + j, k, -1 + n] + aux[1 + 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: A148520 A148521 A303839 * A141160 A113275 A280080

Adjacent sequences:  A148519 A148520 A148521 * A148523 A148524 A148525

KEYWORD

nonn,walk

AUTHOR

Manuel Kauers, Nov 18 2008

STATUS

approved

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Last modified May 25 00:59 EDT 2019. Contains 323534 sequences. (Running on oeis4.)