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A150343 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, 1), (0, 0, 1), (0, 1, -1), (1, 0, 1)} 0
1, 2, 7, 23, 90, 342, 1419, 5747, 24650, 103937, 454972, 1965927, 8731818, 38410970, 172386658, 767905109, 3474517190, 15631384733, 71175064831, 322632050843, 1476741022517, 6735705098662, 30962245640221, 141932236782796, 654804745986586, 3014402916515606, 13949927583535594, 64446234748711170 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..27.

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[i, j, -1 + k, -1 + n] + aux[1 + i, 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: A124190 A176578 A047062 * A150344 A150345 A150346

Adjacent sequences:  A150340 A150341 A150342 * A150344 A150345 A150346

KEYWORD

nonn,walk

AUTHOR

Manuel Kauers, Nov 18 2008

STATUS

approved

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Last modified September 20 12:34 EDT 2019. Contains 327235 sequences. (Running on oeis4.)