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 A308718 #16 Aug 10 2020 09:28:39
%S A308718 6,2,6,0,2,0,1,6,5,6,2,6,0,7,3,8,1,1,5,4,4,1,7,1,4,9,8,2,1,6,3,4,4,4,
%T A308718 3,0,7,5,8,3,5,7,7,8,5,5,9,1,7,0,3,6,5,4,5,5,3,3,5,9,8,7,9,7,1,6,9,8,
%U A308718 0,3,7,4,5,6,6,0,8,7,3,1,7,2,1,6,2,7,0,3,6,4,5,1,4,5,1,6,2,8,1,3,2,8,3,4,9,3,4,0,2,1,2,9,2,4,8,5,5,8,1,7
%N A308718 Decimal expansion of Pi*sech(Pi/2)/2.
%F A308718 Equals Product_{k>=1} 1/(1 - (-1)^k/k^2).
%F A308718 Equals Product_{k>=1} (1 - 1/(2*k*(k + 1) + 1)).
%F A308718 Equals Product_{k>=1} (1 - 1/A001844(k)).
%F A308718 Equals Integral_{x=0..oo} cos(x)/cosh(x) dx. - _Amiram Eldar_, Aug 10 2020
%e A308718 0.6260201656260738115441714982163444307583577855917...
%t A308718 RealDigits[Pi Sech[Pi/2]/2, 10, 120][[1]]
%o A308718 (PARI) Pi*(1/cosh(Pi/2))/2 \\ _Michel Marcus_, Jun 20 2019
%Y A308718 Cf. A000290, A001844, A090986, A308714, A308717.
%K A308718 nonn,cons
%O A308718 0,1
%A A308718 _Ilya Gutkovskiy_, Jun 19 2019