OFFSET
1,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..10000
H. S. Wrigge, An Elliptic Integral Identity, Math. Comp. 27 (1973) no 124, p 839.
I. J. Zucker and G. S. Joyce, Special values of the hypergeometric series II, Math. Proc. Camb. Phil. Soc. 131 (2001) 309-319 (2.4)
EXAMPLE
Equals 1.64556839529345803986605168528707271599955702605540103726529213714...
which equals K[sqrt(2)-1] = Pi^(3/2)*sqrt[2+sqrt(2)]/(4*Gamma(5/8)*Gamma(7/8))
= 5.5683279... * 1.8477590650.. / ( 4 * 1.43451884..... * 1.0896523574...).
MAPLE
evalf(EllipticK(sqrt(2)-1));
MATHEMATICA
RealDigits[Pi^(3/2)*Sqrt[2 + Sqrt@2]/(4 Gamma[5/8] Gamma[7/8]), 10, 111][[1]] (* Robert G. Wilson v, Jul 19 2007 *)
K[x_] := EllipticK[x^2/(x^2-1)]/Sqrt[1-x^2]; RealDigits[K[Sqrt[2]-1], 10, 111][[1]] (* Jean-François Alcover, Sep 22 2015 *)
PROG
(PARI) default(realprecision, 100); Pi^(3/2)*sqrt(2 + sqrt(2))/(4* gamma(5/8)*gamma(7/8)) \\ G. C. Greubel, Sep 27 2018
(Magma) SetDefaultRealField(RealField(100)); R:= RealField(); Pi(R)^(3/2)*Sqrt(2 + Sqrt(2))/(4*Gamma(5/8)*Gamma(7/8)); // G. C. Greubel, Sep 27 2018
CROSSREFS
KEYWORD
cons,nonn
AUTHOR
R. J. Mathar, Jul 15 2007
EXTENSIONS
More terms from Robert G. Wilson v, Jul 19 2007
STATUS
approved