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Search: id:A148808
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| A148808 |
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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, 1, 0), (0, 0, 1), (1, 0, -1), (1, 1, -1)} |
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+0
1
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| 1, 1, 3, 8, 26, 84, 315, 1155, 4479, 17879, 72237, 298920, 1254329, 5323120, 22882116, 99271167, 434160320, 1915240840, 8499435683, 37968001495, 170538467281, 769755420661, 3491044143734, 15897506282629, 72677164291744, 333440276296060, 1534802275386455, 7086364716511872, 32811176928714466
(list; graph; listen)
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OFFSET
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0,3
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LINKS
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A. Bostan and M. Kauers, 2008. Automatic Classification of Restricted Lattice Walks, ArXiv 0811.2899.
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MATHEMATICA
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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, j, 1 + k, -1 + n] + aux[i, j, -1 + k, -1 + n] + aux[1 + i, -1 + j, 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}]
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CROSSREFS
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Sequence in context: A000237 A148806 A148807 this_sequence A148809 A151457 A148810
Adjacent sequences: A148805 A148806 A148807 this_sequence A148809 A148810 A148811
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KEYWORD
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nonn,walk
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AUTHOR
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Manuel Kauers (manuel(AT)kauers.de), Nov 18 2008
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