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A148441 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, 0), (-1, -1, 1), (-1, 1, 0), (0, 1, 1), (1, 0, -1)} 0
1, 1, 2, 6, 16, 45, 154, 499, 1634, 5888, 20756, 73719, 274261, 1014619, 3778927, 14390276, 54958618, 210937648, 818267680, 3195429278, 12519044949, 49315252155, 195701199479, 778376463382, 3105865907871, 12473983517469, 50198995811018, 202462882953762, 820779222155122, 3334412574772313 (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, j, 1 + k, -1 + n] + aux[i, -1 + j, -1 + 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, 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: A151391 A166896 A148440 * A098617 A291036 A092687

Adjacent sequences:  A148438 A148439 A148440 * A148442 A148443 A148444

KEYWORD

nonn,walk

AUTHOR

Manuel Kauers, Nov 18 2008

STATUS

approved

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Last modified February 21 11:25 EST 2019. Contains 320372 sequences. (Running on oeis4.)