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 A197391 #12 Apr 10 2021 11:47:48
%S A197391 2,0,7,0,5,3,4,3,2,1,0,0,7,2,5,6,5,9,0,1,3,9,5,8,5,2,2,0,5,5,2,0,4,9,
%T A197391 7,4,4,8,2,4,4,6,5,1,2,0,3,3,5,4,2,1,5,6,1,0,0,0,1,5,0,8,1,0,9,0,2,2,
%U A197391 0,0,3,2,3,6,8,0,3,3,7,1,4,3,2,0,8,1,9,1,4,3,4,0,4,3,9,9,2,1,4
%N A197391 Decimal expansion of least x > 0 having sin(Pi*x/4) = sin(2*x)^2.
%C A197391 The Mathematica program includes a graph. See A197133 for a guide to least x > 0 satisfying sin(b*x) = sin(c*x)^2 for selected b and c.
%e A197391 x=0.20705343210072565901395852205520497448...
%t A197391 b = Pi/4; c = 2; f[x_] := Sin[x]
%t A197391 t = x /. FindRoot[f[b*x] == f[c*x]^2, {x, .2, .21}, WorkingPrecision -> 200]
%t A197391 RealDigits[t](* A197391 *)
%t A197391 Plot[{f[b*x], f[c*x]^2}, {x, 0, 1.2}]
%Y A197391 Cf. A197133.
%K A197391 nonn,cons
%O A197391 0,1
%A A197391 _Clark Kimberling_, Oct 14 2011