OFFSET
1,2
REFERENCES
Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 5.22 Lenz-Ising Constants, p. 400.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Robert Shrock and F. Y. Wu, Spanning Trees on Graphs and Lattices in d Dimensions, arXiv:cond-mat/0004341 [cond-mat.stat-mech], 2000, p. 7.
FORMULA
Equals log(2) + log(3) + H, where H is the auxiliary constant A242967.
Equals Sum_{n>=1} 10*n*(arccoth((3*n) / 2) - 2 * arccoth(3*n)). - Antonio Graciá Llorente, Oct 13 2024
EXAMPLE
1.6153297360972525704681825536190319703612092039029350806543423518...
MATHEMATICA
H = Sqrt[3]/(6*Pi)*PolyGamma[1, 1/6] - Pi/Sqrt[3] - Log[6]; RealDigits[Log[2] + Log[3] + H, 10, 104] // First
(* or *) 3*(Sqrt[3]/Pi)*N[Sum[1/n^2 - 1/(n+4)^2, {n, 1, Infinity, 6}], 104] // RealDigits // First
CROSSREFS
KEYWORD
AUTHOR
Jean-François Alcover, Jul 30 2014
STATUS
approved