A006731 Site percolation series for square lattice.

1, 2, 4, 7, 12, 20, 33, 53, 85, 133, 210, 322, 505, 759, 1192, 1748, 2782, 3931, 6476, 8579, 15216, 17847, 36761, 33612, 93961, 47282, 262987, -16105, 827382, -571524, 2936705, -3661626, 11507775, -18880652, 48169220, -90436605

Offset: 0

Author

N. J. A. Sloane, Simon Plouffe

Keywords

• sign

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

Crossrefs

Cf. A056532.