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 A197578 #9 Apr 10 2021 13:22:01
%S A197578 5,1,3,5,5,8,3,3,4,3,1,1,3,3,7,5,0,3,6,2,6,8,2,6,0,7,9,8,4,0,8,1,1,4,
%T A197578 4,8,1,2,9,4,6,4,7,0,0,6,8,1,8,1,8,8,6,6,0,8,3,4,6,4,5,2,5,2,1,3,1,1,
%U A197578 4,3,7,5,8,6,0,1,5,3,8,7,6,4,6,0,4,9,2,0,6,9,7,9,8,6,3,8,3,0,2
%N A197578 Decimal expansion of least x > 0 having cos(Pi*x) = cos(3*x)^2.
%C A197578 The Mathematica program includes a graph. See A197476 for a guide for the least x > 0 satisfying cos(b*x) = cos(c*x)^2 for selected b and c.
%e A197578 x=0.51355833431133750362682607984081144812946470068...
%t A197578 b = Pi; c = 3; f[x_] := Sin[x]
%t A197578 t = x /. FindRoot[f[b*x] == f[c*x]^2, {x, .51, .52}, WorkingPrecision -> 200]
%t A197578 RealDigits[t] (* A197578 *)
%t A197578 Plot[{f[b*x], f[c*x]^2}, {x, .4, .6}]
%Y A197578 Cf. A197133.
%K A197578 nonn,cons
%O A197578 0,1
%A A197578 _Clark Kimberling_, Oct 16 2011