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A038577
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Number of self-avoiding walks of length n from origin in strip Z X {0,1}.
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1
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1, 3, 6, 12, 20, 36, 58, 100, 160, 268, 430, 708, 1140, 1860, 3002, 4876, 7880, 12772, 20654, 33444, 54100, 87564, 141666, 229252, 370920, 600196, 971118, 1571340, 2542460, 4113828, 6656290, 10770148
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| For n>=2, a(n) coincides with A110935. [From Eric S Rowland (erowland(AT)math.rutgers.edu), Mar 09 2009]
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REFERENCES
| J. Labelle, Self-avoiding walks and polyominoes in strips, Bull. ICA, 23 (1998), 88-98.
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LINKS
| D. Zeilberger, [math/9506214] Self avoiding walks, the language of science and Fibonacci numbers
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FORMULA
| G.f.: (1+2*t-t^3-t^4+t^7)/(1-t)^2/(1+t)^2/(1-t-t^2).
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MAPLE
| f := n->if n mod 2 = 0 then 8*fibonacci(n)-n else 8*fibonacci(n)-4; fi;
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CROSSREFS
| Sequence in context: A006128 A079983 A028926 * A028925 A028924 A034738
Adjacent sequences: A038574 A038575 A038576 * A038578 A038579 A038580
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KEYWORD
| nonn,walk,easy
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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