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Search: id:A151362
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| A151362 |
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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 2 n steps taken from {(-1, -1), (-1, 0), (-1, 1), (1, -1), (1, 0), (1, 1)} |
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+0
1
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| 1, 2, 18, 255, 4522, 91896, 2047452, 48748986, 1220457810, 31779889284, 854110511124, 23559266827278, 664125694509564, 19070108145820400, 556345776173277960, 16455889048642607295, 492658546882981692690, 14907686709710614053300, 455413194094843994648100
(list; graph; listen)
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OFFSET
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0,2
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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[-1 + i, j, -1 + n] + aux[-1 + i, 1 + j, -1 + n] + aux[1 + i, -1 + j, -1 + n] + aux[1 + i, j, -1 + n] + aux[1 + i, 1 + j, -1 + n]]; Table[aux[0, 0, 2 n], {n, 0, 25}]
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CROSSREFS
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Sequence in context: A121429 A109517 A143138 this_sequence A099880 A141009 A143154
Adjacent sequences: A151359 A151360 A151361 this_sequence A151363 A151364 A151365
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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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