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Search: id:A149928
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A149928 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, 0, 1), (0, 1, 0), (1, -1, -1), (1, 0, 0)} +0
1
1, 2, 5, 15, 48, 166, 597, 2215, 8510, 33266, 132505, 537363, 2202785, 9140543, 38334918, 162006061, 690358870, 2962720562, 12787564112, 55521222256, 242295294818, 1062048148918, 4675861534171, 20666381911613, 91659316769501, 407917282709291, 1820948836147556, 8151519838832373 (list; graph; listen)
OFFSET

0,2

LINKS

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, k, -1 + n] + aux[-1 + i, 1 + j, 1 + k, -1 + n] + aux[i, -1 + j, k, -1 + n] + aux[1 + i, 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: A149927 A035350 A006570 this_sequence A003430 A149929 A149930

Adjacent sequences: A149925 A149926 A149927 this_sequence A149929 A149930 A149931

KEYWORD

nonn,walk

AUTHOR

Manuel Kauers (manuel(AT)kauers.de), Nov 18 2008

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.


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