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A006739 Site percolation series for hexagonal lattice.
(Formerly M2654)
2
1, 3, 7, 15, 31, 62, 122, 235, 448, 842, 1572, 2904, 5341, 9743, 17718, 32009, 57701, 103445, 185165, 329904, 587136, 1040674, 1843300, 3253020, 5738329, 10090036, 17736533, 31086416, 54484239, 95220744, 166451010, 290209573 (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

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

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

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. Jensen, More terms

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

CROSSREFS

Sequence in context: A034480 A218281 A057703 * A119407 A224521 A269167

Adjacent sequences:  A006736 A006737 A006738 * A006740 A006741 A006742

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Simon Plouffe

STATUS

approved

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Last modified January 20 23:20 EST 2019. Contains 319343 sequences. (Running on oeis4.)