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A173380 Number of n-step walks on square lattice (no points repeated, no adjacent points unless consecutive in path). 2
1, 4, 12, 28, 68, 164, 396, 940, 2244, 5324, 12668, 29940, 71012, 167468, 396172, 932628, 2201636, 5175268, 12195660, 28632804, 67374292, 158017740, 371354012 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Fisher and Hiley give 396204 as their last term instead of 396172 (see A002932).  Douglas McNeil confirms 396172 (see seqfan discussion).

Comment from N. J. A. Sloane, Nov 27 2010: Joseph Myers has discovered that several of the sequences listed by Fisher and Riley (1961) contained errors. R. J. Mathar comments that this article has 62 citations in http://adsabs.harvard.edu/abs/1961JChPh..34.1253F and that clicking through these with the "Citations to the Article (62)" button is one way to check the numbers by searching for corrections.

REFERENCES

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

Table of n, a(n) for n=0..22.

M. E. Fisher and B. J. Hiley, Configuration and free energy of a polymer molecule with solvent interaction, J. Chem. Phys., 34 (1961), 1253-1267.

A. M. Nemirovsky et al., Marriage of exact enumeration and 1/d expansion methods: lattice model of dilute polymers, J. Statist. Phys., 67 (1992), 1083-1108.

Sequence Fans Mailing list, discussion of this sequence, November 2010

CROSSREFS

Sequence in context: A028399 A173033 A034508 * A002932 A242079 A121312

Adjacent sequences:  A173377 A173378 A173379 * A173381 A173382 A173383

KEYWORD

nonn,walk,nice

AUTHOR

Joseph Myers, Nov 22 2010

STATUS

approved

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Last modified June 25 00:41 EDT 2017. Contains 288708 sequences.