A084243 Decimal expansion of c = Product_{k>=1} (1 + 1/k^2)^2.

1, 3, 5, 1, 3, 5, 4, 8, 8, 0, 3, 1, 4, 6, 8, 6, 2, 7, 3, 1, 7, 2, 3, 8, 1, 5, 0, 5, 5, 9, 9, 3, 1, 2, 0, 7, 8, 2, 9, 6, 2, 6, 1, 4, 3, 2, 7, 9, 7, 8, 1, 7, 9, 9, 9, 6, 2, 2, 5, 3, 7, 9, 9, 1, 7, 6, 0, 8, 7, 9, 6, 9, 1, 2, 8, 3, 5, 8, 1, 5, 4, 0, 3, 1, 7, 7, 7, 5, 0, 7, 2, 7, 4, 3, 2, 2, 4, 0, 3, 2, 0, 4, 0, 1, 6

Offset

2,2

References

Bruce C. Berndt, Ramanujan Notebook part II, Integral and asymptotic expansions, Springer Verlag, p. 230, entry 27.

Links

Table of n, a(n) for n=2..106.

Formula

Equals (cosh(2*Pi)-1)/(2*Pi^2).

Equals (sinh(Pi)/Pi)^2. - Bernard Schott, Jan 04 2021

Example

13.513548803146862731723815...

Mathematica

Sinh[Pi]^2/Pi^2 // RealDigits[#, 10, 105]& // First (* Jean-François Alcover, Mar 04 2013 *)

Prog

(PARI) (cosh(2*Pi)-1)/2/Pi^2

Crossrefs

Sequence in context: A021078 A130793 A243854 * A275056 A335960 A248916

Adjacent sequences: A084240 A084241 A084242 * A084244 A084245 A084246

Keyword

cons,nonn

Author

Benoit Cloitre, Jun 21 2003

Status

approved