OFFSET
1,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..10000
Eric Weisstein's MathWorld, Catalan Number
FORMULA
EXAMPLE
1.22636467121674271390992581093973546...
MATHEMATICA
RealDigits[2 (Pi/(9 Sqrt[3])) + 6 ((2 Sqrt[5] Log[GoldenRatio] + 15)/125), 10, 120][[1]]
RealDigits[HypergeometricPFQ[{1, 3/2, 2}, {3/4, 5/4}, 1/16], 10, 120][[1]]
PROG
(PARI) suminf(k=0, (2*k+2)/binomial(4*k+2, 2*k+1)) \\ Indranil Ghosh, Mar 04 2017
(PARI) default(realprecision, 100); 2*Pi/(9*sqrt(3)) + 6*(2*sqrt(5)*log((1+sqrt(5))/2) + 15)/125 \\ G. C. Greubel, Nov 04 2018
(Magma) SetDefaultRealField(RealField(100)); R:=RealField(); 2*Pi(R)/(9*Sqrt(3)) + 6*(2*Sqrt(5)*Log((1+Sqrt(5))/2) + 15)/125; // G. C. Greubel, Nov 04 2018
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Ilya Gutkovskiy, Sep 05 2016
STATUS
approved