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A022445
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Number of self-avoiding closed walks (from 0 to 0) of length 2n in the strip {0, 1, 2} X Z of the square lattice Z X Z.
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1
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1, 0, 4, 10, 34, 94, 222, 516, 1202, 2738, 6110, 13496, 29586, 64350, 139006, 298636
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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REFERENCES
| J. Labelle, Self-avoiding walks and polyominoes in strips, Bull. ICA, 23 (1998), 88-98.
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FORMULA
| G.f.: [ -6x^7+10x^6-18x^5+27x^4-14x^3+10x^2-4x+1]/[(1+x^2)^2(1-2x)^2] (conjectured). - Ralf Stephan, Apr 28 2004
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CROSSREFS
| Sequence in context: A149172 A105680 A066454 * A091003 A140725 A005630
Adjacent sequences: A022442 A022443 A022444 * A022446 A022447 A022448
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KEYWORD
| nonn,walk,easy
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AUTHOR
| Jacques Labelle (labelle.jacques(AT)uqam.ca)
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