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A073016 Decimal expansion of Sum_{n>=1} 1/binomial(2n,n). 6
7, 3, 6, 3, 9, 9, 8, 5, 8, 7, 1, 8, 7, 1, 5, 0, 7, 7, 9, 0, 9, 7, 9, 5, 1, 6, 8, 3, 6, 4, 9, 2, 3, 4, 9, 6, 0, 6, 3, 1, 2, 5, 8, 3, 2, 9, 0, 9, 4, 9, 7, 9, 0, 5, 6, 8, 2, 1, 9, 6, 6, 5, 2, 3, 0, 8, 4, 7, 1, 8, 1, 8, 0, 2, 8, 0, 7, 8, 6, 4, 0, 8, 1, 8, 6, 9, 4, 4, 4, 1, 8, 2, 4, 9, 0, 2, 2, 5, 9, 7, 4, 5, 8, 2, 7 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..104.

Simon Plouffe, sum(1/binomial(2n,n), n=1..infinity)

Renzo Sprugnoli, Sums of Reciprocals of the Central Binomial Coefficients, INTEGERS, 6 (2006), #A27, page 9.

Eric Weisstein's World of Mathematics, Central Binomial Coefficient

FORMULA

Sum_{n>=1} 1/binomial(2n, n) = (9 + 2*sqrt(3)*Pi)/27.

Equals A091682 - 1.

EXAMPLE

0.7363998587187150779097951683649234960631258329094979056821966523...

MATHEMATICA

RealDigits[ N[ (9 + 2*Sqrt[3]*Pi)/27, 110]] [[1]]

PROG

(PARI) (2*Pi*sqrt(3)+9)/27 \\ Michel Marcus, Aug 10 2014

CROSSREFS

Cf. A000984 (central binomial coefficients), A091682.

Sequence in context: A198425 A246203 A091682 * A238695 A019819 A215693

Adjacent sequences:  A073013 A073014 A073015 * A073017 A073018 A073019

KEYWORD

cons,nonn

AUTHOR

Robert G. Wilson v, Aug 03 2002

STATUS

approved

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Last modified July 8 01:25 EDT 2020. Contains 335502 sequences. (Running on oeis4.)