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A150857 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), (1, 1, -1), (1, 1, 1)} 0
1, 2, 8, 32, 142, 626, 2880, 13252, 62178, 292358, 1388980, 6614360, 31693270, 152181850, 733673768, 3543512172, 17162220682, 83250135150, 404649688540, 1969439907776, 9600179726462, 46848918460354, 228902852194256, 1119478639450196, 5480396659403698, 26851166934135382, 131665775375554820 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..26.

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, 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: A150855 A150856 A105483 * A150858 A150859 A150860

Adjacent sequences:  A150854 A150855 A150856 * A150858 A150859 A150860

KEYWORD

nonn,walk

AUTHOR

Manuel Kauers, Nov 18 2008

STATUS

approved

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Last modified May 26 10:17 EDT 2022. Contains 354086 sequences. (Running on oeis4.)