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 A197700 #13 Mar 31 2023 17:28:14
%S A197700 4,3,1,3,4,8,7,1,9,1,5,0,7,9,3,5,1,4,4,2,6,7,9,3,8,3,7,1,4,5,6,7,5,3,
%T A197700 3,2,3,9,7,9,5,3,2,3,5,5,9,7,1,7,3,1,5,2,6,0,6,3,0,8,1,4,2,0,9,9,7,6,
%U A197700 2,9,1,1,6,7,7,7,2,3,1,0,6,0,7,3,2,2,0,7,0,7,4,0,2,1,8,5,9,4,9
%N A197700 Decimal expansion of Pi/(1 + 2*Pi).
%C A197700 Least x > 0 such that sin(b*x) = cos(c*x) (and also sin(c*x) = cos(b*x)), where b=1/2 and c=Pi; see the Mathematica program for a graph and A197682 for a discussion and guide to related sequences.
%H A197700 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>
%e A197700 0.4313487191507935144267938371456753323979...
%t A197700 b = 1/2; c = Pi;
%t A197700 t = x /. FindRoot[Sin[b*x] == Cos[c*x], {x, .43, .44}]
%t A197700 N[Pi/(2*b + 2*c), 110]
%t A197700 RealDigits[%] (* A197700 *)
%t A197700 Simplify[Pi/(2*b + 2*c)]
%t A197700 Plot[{Sin[b*x], Cos[c*x]}, {x, 0, 1}]
%t A197700 RealDigits[Pi/(1+2 Pi),10,120][[1]] (* _Harvey P. Dale_, Mar 31 2023 *)
%o A197700 (PARI) 1/(1/Pi+2) \\ _Charles R Greathouse IV_, Sep 30 2022
%Y A197700 Cf. A197682.
%K A197700 nonn,cons
%O A197700 0,1
%A A197700 _Clark Kimberling_, Oct 17 2011