OFFSET
1,3
REFERENCES
Steven R. Finch, Mathematical Constants, Encyclopedia of Mathematics and its Applications, vol. 94, Cambridge University Press, 2003, Section 1.5.4, p. 34.
LINKS
Michael I. Shamos, A catalog of the real numbers, (2007). See p. 134.
FORMULA
Equals Product_{n>=1} (1 - 1/(2*n + 1)^2)^(-1)^n (see Finch).
Equals Product_{n>=1} (4*n - 1)^2*((4*n + 1)^2 - 1)/(((4*n - 1)^2 - 1)*(4*n + 1)^2) (see Shamos).
Equals 2*(Gamma(5/4)/Gamma(3/4)^2.
Equals A254794/2. - Hugo Pfoertner, Oct 31 2024
EXAMPLE
1.09421980761323831941838497035223227162968636141...
MATHEMATICA
RealDigits[Gamma[1/4]^4/(16Pi^2), 10, 100][[1]]
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Stefano Spezia, Oct 31 2024
STATUS
approved