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Search: id:A150920
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| A150920 |
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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, -1), (1, -1, 1), (1, 1, 0), (1, 1, 1)} |
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+0
1
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| 1, 2, 9, 32, 155, 644, 3175, 14098, 69976, 321879, 1602721, 7531433, 37563469, 179013811, 893681771, 4300873876, 21483003773, 104127014063, 520295910233, 2535398215467, 12671477292433, 62004023022238, 309928733352159, 1521498848117653, 7605955483533491, 37437013573708917, 187158809268065886
(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, -1 + j, -1 + k, -1 + n] + aux[-1 + i, -1 + j, k, -1 + n] + aux[-1 + i, 1 + j, -1 + k, -1 + n] + aux[1 + 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: A150917 A150918 A150919 this_sequence A013501 A114853 A110376
Adjacent sequences: A150917 A150918 A150919 this_sequence A150921 A150922 A150923
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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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