A091682 Decimal expansion of 2*(18 + sqrt(3)*Pi)/27.

1, 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

Offset

1,2

Links

G. C. Greubel, Table of n, a(n) for n = 1..25000

Michael Penn, So many factorials!!!, YouTube video, 2020.

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

Eric Weisstein's World of Mathematics, Factorial Sums

Index entries for transcendental numbers

Formula

Equals Sum_{n >= 0} 1/binomial(2*n,n). [See Renzo Sprugnoli reference]

Equals A073016 plus 1. - R. J. Mathar, Sep 08 2008

Example

1.736399858718715077909795168364923496063125832909497905682196652308471818...

Mathematica

RealDigits[N[(2 (18 + Pi Sqrt@3))/27, 120]] // First (* Michael De Vlieger, Sep 11 2015 *)

Prog

(PARI) default(realprecision, 2000); 2*(18 + sqrt(3)*Pi)/27 \\ Anders Hellström, Sep 11 2015
(Magma)
m:= 510; R:=RealField(m); SetDefaultRealField(R);
Prune(Reverse(IntegerToSequence(Floor(( 2*(18 + Sqrt(3)*Pi(R))/27 )*10^(Floor(m/2)) )))); // G. C. Greubel, Sep 06 2025
(SageMath)
numerical_approx( 2*(18 + sqrt(3)*pi)/27 , digits=265 ) # G. C. Greubel, Sep 06 2025

Crossrefs

Cf. A248179: decimal expansion of Sum_{h >= 0} 1/binomial(2*h+1,h).

Cf. A000984, A073016.

Sequence in context: A246203 A392729 A354627 * A073016 A238695 A019819

Adjacent sequences: A091679 A091680 A091681 * A091683 A091684 A091685

Keyword

nonn,cons

Author

Eric W. Weisstein, Jan 28 2004

Status

approved