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Search: id:A149820
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| A149820 |
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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), (0, 1, -1), (0, 1, 0), (1, 0, 0)} |
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+0
1
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| 1, 2, 4, 10, 28, 80, 247, 793, 2558, 8550, 29174, 99856, 348717, 1233071, 4370391, 15686057, 56763062, 205799392, 752476359, 2767134060, 10192178158, 37765951585, 140525915462, 523621511694, 1959695454184, 7357711578218, 27658399144870, 104318355674896, 394433880972610, 1492987311881850
(list; graph; listen)
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OFFSET
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0,2
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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, j, k, -1 + n] + aux[i, -1 + j, k, -1 + n] + aux[i, -1 + 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}]
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CROSSREFS
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Sequence in context: A148109 A099216 A149819 this_sequence A149821 A149822 A034472
Adjacent sequences: A149817 A149818 A149819 this_sequence A149821 A149822 A149823
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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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