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A077482
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Number of self-avoiding walks on square lattice trapped after n steps.
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14
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1, 2, 11, 25, 95, 228, 752, 1860, 5741, 14477, 42939, 109758, 317147, 818229, 2322512, 6030293, 16900541, 44079555, 122379267, 320227677, 882687730, 2315257359, 6346076015, 16675422679, 45502168379, 119728011251, 325510252108, 857400725204
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OFFSET
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7,2
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COMMENTS
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Only 1/8 of all possible walks is counted by selecting the first step in +x direction and requiring the first step changing y to be positive.
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REFERENCES
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LINKS
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EXAMPLE
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a(7) = 1 because there is only 1 self-trapping walk with 7 steps: (0,0)(1,0)(1,1)(1,2)(0,2)(-1,2)(-1,1)(0,1); a(8) = 2 because there are 2 self-trapping walks with 8 steps: (0,0)(1,0)(2,0)(2,1)(2,2)(1,2)(0,2)(0,1)(1,1) and (0,0)(1,0)(1,1)(2,1)(3,1)(3,0)(3,-1)(2,-1)(2,0).
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PROG
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(Fortran) c Program provided at given link.
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CROSSREFS
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KEYWORD
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more,nonn,walk
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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