OFFSET
1,1
LINKS
D. H. Lehmer, Interesting series involving the Central Binomial Coefficient, Am. Math. Monthly 92, no 7 (1985) 449-457.
FORMULA
Equals 4*Sum_{n>=0} binomial(8*n,4*n)/8^(4*n).
EXAMPLE
4.0715942738206731530648... = 4 * 1.017898568455...
MAPLE
sqrt(2)+sqrt(6)/3+2*sqrt(2/5+1/sqrt(5)) ;
MATHEMATICA
RealDigits[Sqrt[2] + Sqrt[6]/3 + 2*Sqrt[2/5 + 1/Sqrt[5]], 10, 100][[1]] (* G. C. Greubel, Oct 02 2018 *)
PROG
(PARI) default(realprecision, 100); sqrt(2)+sqrt(6)/3+2*sqrt(2/5+1/sqrt(5)) \\ G. C. Greubel, Oct 02 2018
(Magma) SetDefaultRealField(RealField(100)); Sqrt(2)+Sqrt(6)/3+2*Sqrt(2/5+1/Sqrt(5)); // G. C. Greubel, Oct 02 2018
CROSSREFS
KEYWORD
AUTHOR
R. J. Mathar, Mar 04 2009
STATUS
approved