Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #14 May 22 2023 02:45:40
%S 2,9,6,1,7,3,9,1,5,3,7,9,7,3,1,4,9,6,7,8,7,4,0,9,0,3,8,6,0,2,3,3,9,4,
%T 6,4,8,1,8,4,1,9,5,8,6,2,5,4,5,9,1,3,7,0,1,9,2,0,2,7,1,5,6,2,3,1,4,5,
%U 0,1,7,9,5,6,4,0,3,2,9,6,1,5,2,1,5,8,1,8,2,6,4,6,2,5,7,2,2,2,1,1,6,6,0,6,6
%N Vertex solid angle (steradians) in a regular dodecahedron.
%H Stanislav Sykora, <a href="/A236558/b236558.txt">Table of n, a(n) for n = 1..2000</a>
%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Platonic_solid">Platonic solid</a>.
%F Equals Pi - arctan(2/11).
%e 2.9617391537973149678740903860233946481841958625459137019202715623145...
%t RealDigits[Pi - ArcTan[2/11], 10, 120][[1]] (* _Amiram Eldar_, May 22 2023 *)
%o (PARI) Pi-atan(2/11)
%Y Cf. Analogs: A236555 (tetrahedron), A236556 (octahedron), A019669 (cube), A236557 (icosahedron).
%K nonn,cons,easy
%O 1,1
%A _Stanislav Sykora_, Jan 28 2014