A002919 High-temperature series for susceptibility for the spin-1/2 Ising model on hexagonal lattice.

1, 6, 24, 90, 318, 1098, 3696, 12270, 40224, 130650, 421176, 1348998, 4299018, 13635630, 43092888, 135698970, 426144654, 1334488074, 4170038328, 13001153910, 40464412482, 125706293478, 389962873920, 1207855307874, 3736709089176, 11544946664622, 35633199126576

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• nice

Comments

Previous name was: Susceptibility for hexagonal lattice.

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, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
• N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

• G. Nebe and N. J. A. Sloane, Home page for hexagonal (or triangular) lattice A2
• M. F. Sykes, D. G. Gaunt, P. D. Roberts and J. A. Wyles, High temperature series for the susceptibility of the Ising model, I. Two dimensional lattices, J. Phys. A 5 (1972) 624-639.

Crossrefs

Cf. A002910, A002920, A047709.

Formula

a(n) = A002910(2*n), cf. A002920. - Andrey Zabolotskiy, Mar 01 2021

Extensions

New name and more terms using A002920 from Andrey Zabolotskiy, Mar 03 2021