

A006742


Series for second perpendicular moment of hexagonal lattice.
(Formerly M2020)


1



2, 12, 46, 144, 402, 1040, 2548, 5992, 13632, 30220, 65486, 139404, 291770, 602908, 1229242, 2482792, 4959014, 9836840, 19323246, 37773464, 73182570, 141345292, 270647584, 517513972, 980893354
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OFFSET

1,1


COMMENTS

The hexagonal lattice is the familiar 2dimensional 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 = 1..82
I. G. Enting, A, J. Guttmann and I. Jensen, LowTemperature Series Expansions for the Spin1 Ising Model, J. Phys. A. 27 (21) (1994) 69877006. [arxiv:heplat/9410005]
J. W. Essam, A. J. Guttmann and K. De'Bell, On twodimensional directed percolation, J. Phys. A 21 (19) (1988), 38153832.
I. Jensen, More terms
Iwan Jensen, Anthony J. Guttmann, Series expansions of the percolation probability for directed square and honeycomb lattices, J. Phys. A 28 (1995), no. 17, 48134833.
G. Nebe and N. J. A. Sloane, Home page for hexagonal (or triangular) lattice A2


CROSSREFS

Sequence in context: A046991 A188982 A061990 * A003993 A129018 A302447
Adjacent sequences: A006739 A006740 A006741 * A006743 A006744 A006745


KEYWORD

sign,changed


AUTHOR

N. J. A. Sloane, Simon Plouffe


STATUS

approved



