0,2

The hexagonal lattice is the familiar 2-dimensional lattice in which each point has 6 neighbors. This is sometimes called the triangular lattice.

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

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

M. E. Fisher and M. F. Sykes, Excluded-volume problem and the Ising model of ferromagnetism, Phys. Rev. 114 (1959), 45-58.

A. J. Guttmann, Asymptotic analysis of power-series expansions, pp. 1-234 of C. Domb and J. L. Lebowitz, editors, Phase Transitions and Critical Phenomena. Vol. 13, Academic Press, NY, 1989.

A. J. Guttmann and J. Wang, The extension of self-avoiding random walk series in two dimensions, J. Phys. A 24 (1991), 3107-3109.

B. D. Hughes, Random Walks and Random Environments, Oxford 1995, vol. 1, p. 459.

J. L. Martin, M. F. Sykes and F. T. Hioe, Probability of initial ring closure for self-avoiding walks on the face-centered cubic and triangular lattices, J. Chem. Phys., 46 (1967), 3478-3481.

D. C. Rapaport, J. Phys. A 18 (1985), L201.

S. Redner, Distribution functions in the interior of polymer chains, J. Phys. A 13 (1980), 3525-3541.

M. F. Sykes, Some counting theorems in the theory of the Ising problem and the excluded volume problem, J. Math. Phys., 2 (1961), 52-62.

I. Jensen, Table of n, a(n) for n = 0..40 [from the Jensen link below]

I. Jensen, Series Expansions for Self-Avoiding Walks

G. Nebe and N. J. A. Sloane, Home page for hexagonal (or triangular) lattice A2

Cf. A036418.

Sequence in context: A030280 A034545 A002920 this_sequence A125316 A092439 A082149

Adjacent sequences: A001331 A001332 A001333 this_sequence A001335 A001336 A001337

nonn,walk,nice

N. J. A. Sloane (njas(AT)research.att.com).