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 A197510 #10 Feb 16 2025 05:27:24
%S A197510 6,6,3,4,9,0,0,4,6,0,5,6,6,3,7,3,2,0,7,8,9,8,3,6,1,6,6,9,1,5,1,9,0,2,
%T A197510 1,3,3,2,1,5,0,3,2,7,9,6,4,5,8,6,8,0,6,0,0,9,3,9,2,7,8,8,8,1,7,1,0,9,
%U A197510 3,2,8,4,7,9,2,1,9,4,6,9,2,3,6,6,4,7,1,7,6,8,4,0,2,6,3,8,9,5,1
%N A197510 Decimal expansion of least x > 0 having cos(2*x) = cos(Pi*x)^2.
%C A197510 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.
%C A197510 This number is irrational. I cannot prove it to be algebraic or transcendental. - _Charles R Greathouse IV_, Feb 16 2025
%e A197510 0.66349004605663732078983616691519021...
%t A197510 b = 2; c = Pi; f[x_] := Cos[x]
%t A197510 t = x /. FindRoot[f[b*x] == f[c*x]^2, {x, .6, .7}, WorkingPrecision -> 110]
%t A197510 RealDigits[t] (* A197510 *)
%t A197510 Plot[{f[b*x], f[c*x]^2}, {x, 0, 1}]
%Y A197510 Cf. A197476.
%K A197510 nonn,cons
%O A197510 0,1
%A A197510 _Clark Kimberling_, Oct 15 2011