This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A258147 #12 Oct 01 2022 00:16:06 %S A258147 3,9,1,0,0,2,2,1,8,9,5,5,7,7,0,6,4,1,9,1,1,0,0,3,4,1,7,5,1,0,1,8,1,9, %T A258147 4,5,9,6,7,9,7,3,4,2,6,4,8,3,3,4,6,3,4,0,2,6,6,9,8,3,6,5,6,5,2,1,1,5, %U A258147 1,5,1,4,9,3,2,0,3,1,7,6,9 %N A258147 Decimal expansion of (4 - 3*sqrt(3)/Pi)/6: ratio of the area of a circular segment with central angle 2*Pi/3 and the area of the corresponding circular half-disk. %C A258147 See the comments on A258146. %C A258147 This is also the ratio of the area of a circular disk (radius R) without an inscribed central rectangle (2*x = R, 2*y = sqrt(3)*R) together with the two opposing circular segments each with central angle Pi/3 and the area Pi*R^2 of the circular disk. %H A258147 G. C. Greubel, <a href="/A258147/b258147.txt">Table of n, a(n) for n = 0..5000</a> %H A258147 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a> %F A258147 2/3 - sqrt(3)/(2*Pi) = 0.39100221895577064191100... %t A258147 RealDigits[2/3 - Sqrt[3]/(2*Pi), 10, 50][[1]] (* _G. C. Greubel_, Oct 19 2017 *) %o A258147 (PARI) 2/3 - sqrt(3)/(2*Pi) \\ _Michel Marcus_, Oct 19 2017 %Y A258147 Cf. A258146, A258148. %K A258147 nonn,cons,easy %O A258147 0,1 %A A258147 _Wolfdieter Lang_, May 31 2015