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A148364 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, 0, 1), (0, 0, 1), (1, -1, 0), (1, 1, -1)} 0
1, 1, 2, 5, 15, 47, 153, 515, 1781, 6290, 22593, 82141, 301643, 1117894, 4173685, 15679942, 59231389, 224775911, 856426691, 3274980603, 12562759119, 48323739885, 186348608027, 720198605807, 2788959419659, 10819918605211, 42044943533093, 163623798367005, 637635663128808, 2487921395396235 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..29.

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[i, j, -1 + k, -1 + n] + aux[1 + i, 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: A071735 A148363 A350434 * A172405 A149915 A149916

Adjacent sequences:  A148361 A148362 A148363 * A148365 A148366 A148367

KEYWORD

nonn,walk

AUTHOR

Manuel Kauers, Nov 18 2008

STATUS

approved

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Last modified January 20 00:45 EST 2022. Contains 350467 sequences. (Running on oeis4.)