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%I #15 Jun 11 2023 02:56:16
%S 0,3,9,4,3,8,1,8,8,7,1,3,5,8,6,4,8,1,2,0,5,1,5,1,7,8,5,7,3,8,9,1,9,0,
%T 5,6,3,7,7,3,8,2,8,9,2,5,2,4,2,8,8,6,2,7,2,3,7,1,4,7,5,1,6,4,9,1,8,7,
%U 0,5,1,5,5,9,9,6,1,3,8,1,2,2,5,5,5,9,4,0,9,1,9,1,2,5,4,4,1,6,6,7,9,5,4,1,4,8
%N Decimal expansion of the fraction of the full solid angle subtended by an equilateral spherical triangle with a side length of 1 radian.
%C Same quantity as in A243710, but expressed as a fraction of the full solid angle of 4*Pi.
%H Stanislav Sykora, <a href="/A243711/b243711.txt">Table of n, a(n) for n = 0..2001</a>
%F Equals A243710/(4*Pi).
%e 0.0394381887135864812051517857389190563773828925242886272371475...
%t RealDigits[ArcTan[Sqrt[Tan[3/4]*Tan[1/4]^3]]/Pi, 10, 120, -1][[1]] (* _Amiram Eldar_, Jun 11 2023 *)
%o (PARI) atan(sqrt(tan(3/4)*tan(1/4)^3))/Pi
%Y Cf. A243710.
%K nonn,cons,easy
%O 0,2
%A _Stanislav Sykora_, Jun 08 2014