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Search: id:A151365
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| A151365 |
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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), (0, 1), (1, 1)} |
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+0
1
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| 1, 0, 2, 2, 11, 27, 101, 348, 1237, 4752, 17552, 69635, 269504, 1085729, 4351437, 17775548, 72934213, 302080006, 1259717600, 5283979096, 22304022387, 94582158638, 403155327233, 1725391432093, 7415018474585, 31980782229030, 138409663709656, 600908838337016, 2616559379817830
(list; graph; listen)
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OFFSET
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0,3
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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[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: A090525 A126806 A121871 this_sequence A090527 A014220 A089544
Adjacent sequences: A151362 A151363 A151364 this_sequence A151366 A151367 A151368
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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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