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 A373642 #11 Aug 20 2024 01:53:32
%S A373642 1,4,8,9,5,5,0,2,4,8,8,1,3,8,2,6,4,6,8,5,8,4,1,1,5,2,4,4,5,2,8,9,4,3,
%T A373642 6,2,5,3,9,3,7,1,5,6,0,7,5,1,5,8,6,9,8,3,2,2,7,1,3,2,6,8,5,7,9,1,2,6,
%U A373642 9,5,7,4,5,8,1,6,8,2,0,6,7,7,0,9,6,4,8,5,3,9,1,9,4
%N A373642 Decimal expansion of Sum_{k>=1} (sin(Pi/k))^(2k).
%H A373642 Lewis Trem, <a href="https://math.stackexchange.com/questions/3750077">Infinite sum of ...</a>, Math StackExchange, Jul 8 2020.
%e A373642 0^2 + 1^4 + (0.86602...)^6 + (0.70710..)^8 + (0.58778..)^10 + ... = 1.4895502488138264685841...
%o A373642 (PARI) sumpos(k = 1, sin(Pi/k)^(2*k)) \\ _Amiram Eldar_, Aug 20 2024
%Y A373642 Cf. A269611, A010527 (sin Pi/3), A010503 (sin Pi/4), A019845 (sin Pi/5).
%K A373642 nonn,cons
%O A373642 1,2
%A A373642 _R. J. Mathar_, Jun 12 2024