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 A197688 #20 Dec 30 2023 15:05:50
%S A197688 8,7,9,8,0,1,6,9,2,9,7,6,8,8,5,2,4,8,1,7,9,0,4,2,7,4,9,0,2,7,4,2,6,7,
%T A197688 6,7,5,9,8,3,7,4,8,8,6,4,7,5,3,7,8,4,8,2,5,3,1,8,9,9,7,3,6,2,5,1,6,8,
%U A197688 0,4,2,6,1,6,7,8,0,6,1,9,5,3,7,3,7,0,0,9,1,5,8,7,3,8,5,2,6,7,0
%N A197688 Decimal expansion of 2*Pi/(4+Pi).
%C A197688 Least x>0 such that sin(bx)=cos(cx) (and also sin(cx)=cos(bx)), where b=1 and c=pi/4; see the Mathematica program for a graph and A197682 for a discussion and guide to related sequences.
%C A197688 This number is the pressure drag coefficient for Kirchhoff flow past a plate, calculated by Kirchhoff (1969) for an infinitely long plate; see References. - _Peter J. C. Moses_ and _Clark Kimberling_, Sep 07 2013
%D A197688 Herbert Oertel and P. Erhard, Prandtl-Essentials of Fluid Mechanics, Springer, 2010, pages 163-164.
%H A197688 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>
%e A197688 x=0.8798016929768852481790427490274267675983748864...
%t A197688 b = 1; c = Pi/4;
%t A197688 t = x /. FindRoot[Sin[b*x] == Cos[c*x], {x, .8, .9}]
%t A197688 N[Pi/(2*b + 2*c), 110]
%t A197688 RealDigits[%] (* A197688 *)
%t A197688 Simplify[Pi/(2*b + 2*c)]
%t A197688 Plot[{Sin[b*x], Cos[c*x]}, {x, 0, Pi/2}]
%t A197688 RealDigits[(2 Pi)/(4+Pi),10,120][[1]] (* _Harvey P. Dale_, Dec 30 2023 *)
%o A197688 (PARI) 2*Pi/(4+Pi) \\ _Charles R Greathouse IV_, Jul 22 2014
%Y A197688 Cf. A197682.
%K A197688 nonn,cons
%O A197688 0,1
%A A197688 _Clark Kimberling_, Oct 17 2011