OFFSET
1,3
LINKS
J. M. Borwein, I.J. Zucker and J. Boersma, The evaluation of character Euler double sums, The Ramanujan Journal, April 2008, Volume 15, Issue 3, pp 377-405, see p. 17 c(3).
R. J. Mathar, Table of Dirichlet L-Series and Prime Zeta Modulo Functions for Small Moduli, arXiv:1008.2547 [math.NT], 2010-2015, Table 22.
FORMULA
Equals 7*zeta(3)/8.
Also equals -(1/16)*PolyGamma(2, 1/2). - Jean-François Alcover, Dec 18 2013
Equals Integral_{x=0..Pi/2} x * log(tan(x)) dx. - Amiram Eldar, Jun 29 2020
Equals Integral_{x=0..1} arcsin(x)*arccos(x)/x dx. - Amiram Eldar, Aug 03 2020
EXAMPLE
1.0517997902646449997247708913225187419193630057979365215682376109241...
MATHEMATICA
RealDigits[7 Zeta[3]/8, 10, 90][[1]]
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Bruno Berselli, Dec 04 2013
STATUS
approved