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Search: id:A078797
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| A078797 |
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Sum of square displacements over all self-avoiding n-step walks on square lattice. Numerator of mean square displacement s(n)=a(n)/A046661(n). |
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+0 4
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| 1, 8, 41, 176, 679, 2452, 8447, 28120, 91147, 289324, 902721, 2777112, 8441319, 25398500, 75744301, 224156984, 658855781, 1924932324, 5593580859, 16175728584, 46572304083, 133556779740, 381611332725, 1086759598120
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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A comparison with the conjectured asymptotic behavior of the mean square displacement s(n) over all n-step self-avoiding walks given in E.Weissteins MathWorld article is shown in "Asymptotic Behavior of Mean Square Displacement" at first link
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REFERENCES
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See under A001411
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LINKS
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I. Jensen, Table of n, a(n) for n = 1..59 [from the Jensen link below]
I. Jensen, Series Expansions for Self-Avoiding Walks
Hugo Pfoertner, Results for the 2D Self-Trapping Random Walk
Eric Weisstein's World of Mathematics, Self-Avoiding Walk Connective Constant, Section from World of Mathematics
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FORMULA
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a(n)=sum k=1, A046661(n) ( i_k^2 + j_k^2 ) where (i_k, j_k) are the end points of all different self-avoiding n-step walks
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EXAMPLE
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Example: a(2)=8 because the A046661(2)=3 different self-avoiding 2-step walks end at (1,-1),(1,1)->d^2=2 and at (2,0)->d^2=4, so a(2) = 2*2 + 1*4 = 8 a(3)=41 because the end-points of the 9 different 3-step walks are: (0,-1),(0,1)->d^2=1, (1,-2),(1,2),(2,-1),(2,-1),(2,1),(2,1)->d^2=5, (3,0)->d^2=9. a(3) = 2*1 + 6*5 + 1*9 = 41 See also "Distribution of end point distance" at first link
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PROGRAM
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Source code of "FORTRAN program for distance counting" available at first link
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CROSSREFS
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Cf. A001411, A046661.
Sequence in context: A041116 A135797 A133106 this_sequence A156790 A080840 A026968
Adjacent sequences: A078794 A078795 A078796 this_sequence A078798 A078799 A078800
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KEYWORD
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frac,nonn
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AUTHOR
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Hugo Pfoertner (hugo(AT)pfoertner.org), Dec 05 2002
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