cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A005400 High temperature series for spin-1/2 Heisenberg specific heat on 2D hexagonal lattice.

Original entry on oeis.org

0, 9, 18, -306, -3240, 49176, 1466640, -13626000, -1172668032, 75256704, 1392243773184, 18426692664576, -2213592367094784, -74200148173310976, 4271973657228822528, 294089252618987845632, -8526609981314268364800, -1299100041545138822873088
Offset: 1

Views

Author

Keywords

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).

Crossrefs

Cf. A005399 (susceptibility), A005402 (square lattice).

Extensions

Better description from Steven Finch
a(11)-a(12) added from Oitmaa and Bornilla by Andrey Zabolotskiy, Oct 20 2021
a(13) from Elstner et al. (see table I; signs differ because they consider antiferromagnet, and they mention energy instead of specific heat because the same coefficients are involved, cf. Eqs. (11) and (13) from Oitmaa & Bornilla) added by Andrey Zabolotskiy, Jun 17 2022
a(14)-a(18) from Pierre, Bernu & Messio added by Andrey Zabolotskiy, Nov 25 2024