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A078798 Sum of Manhattan distances over all self-avoiding n-step walks on square lattice. Numerator of mean Manhattan displacement s(n)=a(n)/A046661(n). +0
2
6, 23, 80, 263, 834, 2569, 7764, 23095, 67910, 197607, 570560, 1635331, 4661026, 13212739, 37296004, 104836893, 293710714, 820132581, 2283926980, 6343214871, 17578257134, 48604029143, 134141458280, 369519394643 (list; graph; listen)
OFFSET

2,1

COMMENT

A conjectured asymptotic behavior for the mean Manhattan displacement lim n-> infinity a(n)/(A046661(n)*n^(3/4))=constant is illustrated in "Asymptotic Behavior of Mean Manhattan Displacement" at first link

REFERENCES

See under A001411

LINKS

Hugo Pfoertner, Results for the 2D Self-Trapping Random Walk

FORMULA

a(n)= sum k=1, A046661(n) (|i_k| + |j_k|) where (i_k, j_k) are the end points of all different self-avoiding n-step walks.

EXAMPLE

a(3)=23 because 2 of the A046661(3)=9 walks end at Manhattan distance 1: (0,-1),(0,1) and 7 walks end at Manhattan distance 3: (1,-2),(1,2),2*(2,-1),2*(2,1),(3,0); a(3)=2*1+7*3=23 See also "Distribution of end point distance" at first link

PROGRAM

Source code of "FORTRAN program for distance counting" available at first link

CROSSREFS

Cf. A001411, A046661, A078797.

Sequence in context: A058751 A034359 A114245 this_sequence A027043 A006815 A054491

Adjacent sequences: A078795 A078796 A078797 this_sequence A078799 A078800 A078801

KEYWORD

frac,nonn

AUTHOR

Hugo Pfoertner (hugo(AT)pfoertner.org), Dec 10 2002

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Last modified November 27 14:50 EST 2009. Contains 167570 sequences.


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