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 A006803 Percolation series for hexagonal lattice. (Formerly M2232) 5
 1, 0, 0, -1, 0, -3, 1, -9, 6, -29, 27, -99, 112, -351, 450, -1275, 1782, -4704, 6998, -17531, 27324, -65758, 106211, -247669, 411291, -935107, 1587391, -3535398, 6108103, -13373929, 23438144, -50592067, 89703467, -191306745, 342473589 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,6 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..51 J. Blease, Series expansions for the directed-bond percolation problem, J. Phys C vol 10 no 7 (1977), 917-924. 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 Cf. A006809. Sequence in context: A229759 A185580 A052931 * A197730 A231902 A143495 Adjacent sequences:  A006800 A006801 A006802 * A006804 A006805 A006806 KEYWORD sign AUTHOR STATUS approved

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Last modified October 22 00:52 EDT 2019. Contains 328315 sequences. (Running on oeis4.)