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A022444
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Number of self-avoiding closed walks (from (0,0) to (0,0)) of length 2n in strip {-1, 0, 1} X Z.
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2
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1, 0, 8, 16, 44, 112, 252, 564, 1276, 2840, 6220, 13532, 29292, 63024, 134876, 287428, 610268, 1291336, 2724204, 5731500, 12029260, 25191008, 52646908, 109823636, 228707004, 475533432, 987305612, 2047088764, 4239132716
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OFFSET
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0,3
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REFERENCES
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J. Labelle, Self-avoiding walks and polyominoes in strips, Bull. ICA, 23 (1998), 88-98.
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LINKS
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FORMULA
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G.f.: (-12*x^7+16*x^6-36*x^5+37*x^4-24*x^3+14*x^2-4*x+1) / ((1+x^2)^2*(1-2*x)^2) (conjectured).
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CROSSREFS
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KEYWORD
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nonn,walk,easy
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AUTHOR
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Jacques Labelle (labelle.jacques(AT)uqam.ca)
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EXTENSIONS
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STATUS
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approved
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