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Search: id:A151336
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| A151336 |
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Number of walks within N^2 (the first quadrant of Z^2) starting and ending at (0,0) and consisting of n steps taken from {(-1, -1), (-1, 0), (0, 1), (1, -1)} |
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+0
1
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| 1, 0, 0, 1, 2, 0, 5, 26, 28, 42, 369, 908, 1122, 5773, 23119, 42716, 117508, 549438, 1479612, 3367843, 13480787, 46542736, 115686395, 371629486, 1402498101, 4078027887, 11785376915, 42758254550, 140673861443, 410211643221, 1373805039590, 4780700411490, 14793100980164, 47088191339857, 163599002479471
(list; graph; listen)
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OFFSET
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0,5
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LINKS
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M. Bouquet-Melou and M. Mishna, 2008. Walks with small steps in the quarter plane, ArXiv 0810.4387.
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MATHEMATICA
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aux[i_Integer, j_Integer, n_Integer] := Which[Min[i, j, n] < 0 || Max[i, j] > n, 0, n == 0, KroneckerDelta[i, j, n], True, aux[i, j, n] = aux[-1 + i, 1 + j, -1 + n] + aux[i, -1 + j, -1 + n] + aux[1 + i, j, -1 + n] + aux[1 + i, 1 + j, -1 + n]]; Table[aux[0, 0, n], {n, 0, 25}]
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CROSSREFS
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Sequence in context: A080901 A137260 A153059 this_sequence A047918 A138701 A050821
Adjacent sequences: A151333 A151334 A151335 this_sequence A151337 A151338 A151339
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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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