A088245 Decimal expansion of 9/(2*Pi^2).

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

Offset: 0

Author

Eric W. Weisstein, Sep 25 2003

Keywords

• nonn
• cons

Comments

The asymptotic density of squarefree numbers not divisible by 3 (A261034). - Amiram Eldar, May 22 2020

Examples

			0.455945326390519971497457584443774375...
		

References

• See the Hardy reference given under A030059, eq. (4.9.4), p. 64, from the corrected formula on p. 65 for s=2. - Wolfdieter Lang, Oct 18 2016

Links

• Eric Weisstein's World of Mathematics, Moebius Function
• Index entries for transcendental numbers

Crossrefs

Cf. A082020, A088246, A030059, A261034.

Programs

Mathematica

RealDigits[N[9/(2 Pi^2), 120]] // First (* Michael De Vlieger, Oct 23 2015 *)

PARI

9/(2*Pi^2) \\ Altug Alkan, Oct 23 2015

Formula

Equals Sum_{n > 0} 1/A030059(n)^2 (the sum of reciprocals of squarefree numbers with an odd number of prime factors). Convergence is very slow. - Michel Lagneau, Oct 23 2015