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A148836 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, 0, 0), (0, 0, -1), (0, 1, 1), (1, -1, 1)} 0
1, 1, 3, 8, 27, 90, 314, 1128, 4153, 15645, 59702, 230787, 903001, 3564992, 14204743, 57014847, 230396765, 936783710, 3828965482, 15730767884, 64921356490, 269039650977, 1119245234734, 4672527853961, 19571504860039, 82229213110248, 346464646169936, 1463723358626057, 6199295747914251 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

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, -1 + k, -1 + n] + aux[i, j, 1 + k, -1 + n] + aux[1 + i, 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: A145792 A148834 A148835 * A148837 A148838 A148839

Adjacent sequences:  A148833 A148834 A148835 * A148837 A148838 A148839

KEYWORD

nonn,walk

AUTHOR

Manuel Kauers, Nov 18 2008

STATUS

approved

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Last modified September 15 16:44 EDT 2019. Contains 327078 sequences. (Running on oeis4.)