A185197 Decimal expansion of 2/Pi^2.

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

Offset: 0

Author

N. J. A. Sloane, Feb 19 2011

Keywords

• cons
• nonn

Comments

Asymptotic density of the even squarefree numbers (A039956). - Amiram Eldar, May 22 2020

Examples

			.20264236728467554288775892641945527780871754934449309769121...
		

References

• C. F. Gauss, Disquisitiones Arithmeticae, Yale, 1965; see p. 360.

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..3000
• Index entries for transcendental numbers

Crossrefs

Cf. A008683, A013661, A039956.

Programs

Mathematica

RealDigits[2/\[Pi]^2,10,100][[1]]  (* Harvey P. Dale, Mar 16 2011 *)

PARI

2/Pi^2 \\ Charles R Greathouse IV, Mar 25 2014

Formula

Equals 1/(3*zeta(2)). - Michel Marcus, Jun 13 2017

Equals -Sum_{k>=1} mu(2*k)/(2*k)^2, where mu is the Möbius function (A008683). - Amiram Eldar, Jul 31 2020