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Search: id:A151344
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| A151344 |
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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)} |
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+0
1
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| 1, 1, 5, 35, 313, 3253, 37540, 467990, 6190709, 85835624, 1236484572, 18384929389, 280749914660, 4386014526625, 69882361534195, 1132723613672240, 18640032332057095, 310881221313870479, 5247411904749163561, 89530524469245596005, 1542486243771208605759, 26810622290131017450845
(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, 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: A027392 A109253 A052797 this_sequence A015683 A000357 A051577
Adjacent sequences: A151341 A151342 A151343 this_sequence A151345 A151346 A151347
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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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