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A148134 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, 1, 0), (1, -1, 0), (1, 0, -1)} 0
1, 1, 2, 4, 11, 28, 79, 244, 756, 2414, 8107, 27640, 95361, 338751, 1222567, 4443525, 16439284, 61649195, 232510867, 887040112, 3421223717, 13262535201, 51824394632, 204265724147, 808816950156, 3221620828563, 12920663336684, 52033194700646, 210517584336915, 856451947014847, 3497061369568127 (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, j, 1 + k, -1 + n] + aux[-1 + i, 1 + j, k, -1 + n] + aux[i, -1 + j, 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: A032101 A005200 A148133 * A151425 A148135 A034768

Adjacent sequences:  A148131 A148132 A148133 * A148135 A148136 A148137

KEYWORD

nonn,walk

AUTHOR

Manuel Kauers, Nov 18 2008

STATUS

approved

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Last modified October 19 11:52 EDT 2018. Contains 316359 sequences. (Running on oeis4.)