OFFSET
0,1
REFERENCES
Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 5.22 Lenz-Ising Constants, p. 396.
LINKS
Andrei Okounkov, Limit shapes, real and imagined, Bull. Amer. Math. Soc. 53 2 (2016), 187-216
Wikipedia, Ising Model.
FORMULA
K_c = (1/2)*log(1 + sqrt(2)) = (1/2)*A091648.
Equals Integral_{0..1} x/sqrt(1 + x^4) dx. - Peter Bala, Oct 28 2019
Equals arcsinh(1)/2. - Peter Luschny, Oct 29 2019
Equals arctanh(sqrt(2)-1). - Amiram Eldar, Feb 09 2024
EXAMPLE
0.4406867935097715126163046624898961545140801641308177053766478...
MATHEMATICA
RealDigits[(1/2)*Log[1 + Sqrt[2]], 10, 102] // First
CROSSREFS
KEYWORD
AUTHOR
Jean-François Alcover, Jul 30 2014
STATUS
approved