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Decimal expansion of (gamma + log(4/Pi))/2, where gamma is Euler's constant.
1

%I #11 Jun 19 2023 06:41:11

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

%T 2,7,7,7,2,9,3,2,3,9,5,8,7,2,5,6,1,2,6,7,7,6,6,7,5,2,0,9,1,1,9,9,7,5,

%U 8,6,0,0,4,1,6,1,1,4,0,1,1,1,8,2,5,2,5,2,2,3,5,0,4,5,4,7,2,0,8,4,4,8,3,1,2

%N Decimal expansion of (gamma + log(4/Pi))/2, where gamma is Euler's constant.

%H Jean-Paul Allouche, Jeffrey Shallit, and Jonathan Sondow, <a href="https://doi.org/10.1016/j.jnt.2006.06.001">Summation of Series Defined by Counting Blocks of Digits</a>, Journal of Number Theory, volume 123, number 1, March 2007, pages 133-143. Also <a href="https://arxiv.org/abs/math/0512399">arXiv:math/0512399</a> [math.NT], 2005-2006.

%F Equals (A001620 + A094640)/2, the mean of Euler's constant and alternating Euler's constant.

%F Equals Sum_{n>=1} A000120(n) / (2*n*(2*n+1)), where A000120 is the number of 1-bits of n in binary. [Allouche, Shallit, Sondow]

%F Equals Sum_{k>=1} (1/(2*k-1) - log(1+1/(2*k-1))). - _Amiram Eldar_, Jun 19 2023

%e 0.40939007008601165264877449082284842...

%t RealDigits[(EulerGamma + Log[4/Pi])/2, 10, 100][[1]] (* _Amiram Eldar_, May 27 2021 *)

%Y Cf. A001620, A094640, A000120.

%K nonn,cons

%O 0,1

%A _Kevin Ryde_, May 27 2021