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A006740 Series for first parallel moment of hexagonal lattice.
(Formerly M3563)
1
0, 4, 20, 68, 196, 512, 1256, 2936, 6628, 14528, 31140, 65414, 135276, 275656, 555216, 1105726, 2182380, 4268906, 8290740, 15984420, 30638312, 58369924, 110665328, 208734268, 392103508, 733311754, 1366650536, 2537201920 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

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

REFERENCES

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

LINKS

I. Jensen, Table of n, a(n) for n = 0..82 (from link below)

I. G. Enting, A, J. Guttmann and I. Jensen, Low-Temperature Series Expansions for the Spin-1 Ising Model, arXiv:hep-lat/9410005, 1994; J. Phys. A. 27 (1994) 6987-7006.

J. W. Essam, A. J. Guttmann and K. De'Bell, On two-dimensional directed percolation, J. Phys. A 21 (1988), 3815-3832.

I. Jensen, More terms

Iwan Jensen, Anthony J. Guttmann, Series expansions of the percolation probability for directed square and honeycomb lattices, arXiv:cond-mat/9509121, 1995; J. Phys. A 28 (1995), no. 17, 4813-4833.

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

CROSSREFS

Sequence in context: A319779 A287244 A123613 * A291526 A303011 A197426

Adjacent sequences:  A006737 A006738 A006739 * A006741 A006742 A006743

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Simon Plouffe

STATUS

approved

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Last modified June 2 14:21 EDT 2020. Contains 334787 sequences. (Running on oeis4.)