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.

Showing 1-6 of 6 results.

A002911 Erroneous version of A047709.

Original entry on oeis.org

0, 0, 1, 0, 12, 4, 129, 122, 1332, 960, 10919, 11372, 132900, 126396, 1299851, 1349784
Offset: 2

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Comments

Previous name was: Susceptibility for hexagonal lattice.
The terms 122 and 10919 are incorrect (not supported by the work cited by the source of this sequence).

References

  • C. Domb, Ising model, in Phase Transitions and Critical Phenomena, vol. 3, ed. C. Domb and M. S. Green, Academic Press, 1974; p. 421.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

A002927 Low temperature series for spin-1/2 Ising magnetic susceptibility on 2D square lattice.

Original entry on oeis.org

0, 0, 1, 8, 60, 416, 2791, 18296, 118016, 752008, 4746341, 29727472, 185016612, 1145415208, 7059265827, 43338407712, 265168691392, 1617656173824, 9842665771649, 59748291677832, 361933688520940, 2188328005246304, 13208464812265559, 79600379336505560, 479025509574159232
Offset: 0

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Comments

The zero-field susceptibility per spin is 4m^2/kT * Sum_{n >= 0} a(n) * u^n, where u = exp(-4J/kT). (m is the magnetic moment of a single spin; this factor may be present or absent depending on the precise definition of the susceptibility.) The b-file has been obtained from the series by Guttmann and Jensen via the substitution r = u/(1-u)^2 and dividing by 4. - Andrey Zabolotskiy, Feb 11 2022

References

  • C. Domb, Ising model, in Phase Transitions and Critical Phenomena, vol. 3, ed. C. Domb and M. S. Green, Academic Press, 1974; p. 421.
  • S. R. Finch, Mathematical Constants, Cambridge, 2003, pp. 391-406.
  • 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).

Crossrefs

Cf. A002906 (high-temperature), A002979 (antiferromagnetic susceptibility), A029872 (specific heat), A002928 (magnetization), A002890 (partition function), A047709 (hexagonal lattice), A002912 (honeycomb), A002926 (cubic lattice), A010115 (spin-1 Ising).

Formula

a(n) ~ c * n^(3/4) * (1 + sqrt(2))^(2*n), where c = 0.0187325517235678... - Vaclav Kotesovec, May 06 2024

Extensions

Corrections and updates from Steven Finch
a(0) = a(1) = 0 prepended, terms a(20) and beyond added by Andrey Zabolotskiy, Feb 10 2022

A002920 High-temperature series in w = tanh(J/kT) for ferromagnetic susceptibility for the spin-1/2 Ising model on hexagonal lattice.

Original entry on oeis.org

1, 6, 30, 138, 606, 2586, 10818, 44574, 181542, 732678, 2935218, 11687202, 46296210, 182588850, 717395262, 2809372302, 10969820358, 42724062966, 166015496838, 643768299018, 2491738141314, 9628130289018, 37146098272266, 143110933254702, 550643544948090
Offset: 0

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Comments

Previous name was: Susceptibility series 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.
The actual susceptibility per spin is this series times m^2/kT. (m is the magnetic moment of a single spin; this factor may be present or absent depending on the precise definition of the susceptibility.)

References

  • C. Domb, Ising model, in Phase Transitions and Critical Phenomena, vol. 3, ed. C. Domb and M. S. Green, Academic Press, 1974; p. 380.
  • 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).

Crossrefs

Formula

G.f.: (h(v(w)) + h(-v(w))) / 2, where h(v) is the g.f. of A002910 and v(w)^2 = w*(1+w)/(1+w^3) [Fisher, p. 979]. - Andrey Zabolotskiy, Mar 01 2021

Extensions

Edited and extended from Chan et al by Andrey Zabolotskiy, Mar 03 2021

A002978 Low-temperature series in y = exp(2J/kT) for antiferromagnetic susceptibility for the Ising model on honeycomb structure.

Original entry on oeis.org

0, 0, 4, 0, 12, 8, 48, 96, 320, 888, 2748, 8384, 26340, 83568, 268864, 873648, 2865216, 9470784, 31525524, 105594912, 355673804, 1204059144, 4094727168, 13983145888, 47932777680, 164881688088, 568990371212, 1969356192624, 6834965581764, 23782468159920
Offset: 1

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Author

Keywords

Comments

Previous name was: Susceptibility series for honeycomb.

References

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

Crossrefs

Formula

From Andrey Zabolotskiy, Mar 03 2021: (Start)
a(n) = 4*A007214(n-3).
G.f.: 8*t(u(y)) - 4*h(y), where t(u) is the g.f. of A047709, h(y) is the g.f. of A002912, and u(y) = y/(1-y+y^2) [Sykes & Fisher, p. 934-935]. (End)

Extensions

New name from and more terms from Chan et al added by Andrey Zabolotskiy, Mar 03 2021

A005399 E.g.f.: high-temperature series in J/2kT for ferromagnetic susceptibility for the spin-1/2 Heisenberg model on hexagonal lattice.

Original entry on oeis.org

1, 6, 48, 408, 3600, 42336, 781728, 13646016, 90893568, -1798204416, 70794720768, 7538546211840, 63813109782528, -12977417912045568, -320549902414196736, 33016479733605777408, 1709506241695601983488
Offset: 0

Views

Author

Keywords

Comments

Previous name was: Susceptibility series 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 and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Cf. A002920 (Ising high-temperature), A047709 (Ising low-temperature), A005400 (series for specific heat, or free energy), A005401 (square lattice), A005402 (specific heat for square lattice).

Extensions

New name from Andrey Zabolotskiy, Mar 03 2021
a(10)-a(12) added from Oitmaa and Bornilla by Andrey Zabolotskiy, Oct 20 2021
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
a(14)-a(16) using Pierre, Bernu & Messio's data added by Andrey Zabolotskiy, Nov 25 2024

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

Original entry on oeis.org

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

Views

Author

Keywords

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).

Crossrefs

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
Showing 1-6 of 6 results.