A005399 - OEIS

%I M4256 #27 Jun 18 2022 04:10:42

%S 1,6,48,408,3600,42336,781728,13646016,90893568,-1798204416,

%T 70794720768,7538546211840,63813109782528,-12977417912045568

%N E.g.f.: high-temperature series in J/2kT for ferromagnetic susceptibility for the spin-1/2 Heisenberg model on hexagonal lattice.

%C Previous name was: Susceptibility series for hexagonal lattice.

%C The hexagonal lattice is the familiar 2-dimensional lattice in which each point has 6 neighbors. This is sometimes called the triangular lattice.

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

%H G. A. Baker Jr., H. E. Gilbert, J. Eve, and G. S. Rushbrooke, <a href="https://doi.org/10.1016/0375-9601(67)90860-2">On the two-dimensional, spin-1/2 Heisenberg ferromagnetic models</a>, Phys. Lett., 25A (1967), 207-209.

%H N. Elstner, R. R. P. Singh and A. P. Young, <a href="https://doi.org/10.1103/PhysRevLett.71.1629">Finite temperature properties of the spin-1/2 Heisenberg antiferromagnet on the triangular lattice</a>, Phys. Rev. Lett., 71 (1993), 1629-1632.

%H G. Nebe and N. J. A. Sloane, <a href="http://www.math.rwth-aachen.de/~Gabriele.Nebe/LATTICES/A2.html">Home page for hexagonal (or triangular) lattice A2</a>

%H J. Oitmaa and E. Bornilla, <a href="https://doi.org/10.1103/PhysRevB.53.14228">High-temperature-series study of the spin-1/2 Heisenberg ferromagnet</a>, Phys. Rev. B, 53 (1996), 14228.

%Y Cf. A002920, A047709, A005400, A005401, A005402.

%K sign,more

%O 0,2

%A _N. J. A. Sloane_

%E New name from _Andrey Zabolotskiy_, Mar 03 2021

%E a(10)-a(12) added from Oitmaa and Bornilla by _Andrey Zabolotskiy_, Oct 20 2021

%E a(0) and a(13) using data from Elstner et al. (see Table I for the values -(-1)^n*n*a(n-1)) added by _Andrey Zabolotskiy_, Jun 17 2022