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A185197
Decimal expansion of 2/Pi^2.
10
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
0,1
COMMENTS
Asymptotic density of the even squarefree numbers (A039956). - Amiram Eldar, May 22 2020
REFERENCES
C. F. Gauss, Disquisitiones Arithmeticae, Yale, 1965; see p. 360.
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
EXAMPLE
.20264236728467554288775892641945527780871754934449309769121...
MATHEMATICA
RealDigits[2/\[Pi]^2, 10, 100][[1]] (* Harvey P. Dale, Mar 16 2011 *)
PROG
(PARI) 2/Pi^2 \\ Charles R Greathouse IV, Mar 25 2014
CROSSREFS
KEYWORD
cons,nonn
AUTHOR
N. J. A. Sloane, Feb 19 2011
STATUS
approved