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 A197518 #7 Feb 16 2025 05:30:30
%S A197518 8,2,5,9,7,9,1,5,6,8,1,1,2,5,0,3,9,4,8,8,2,3,3,9,1,4,2,8,6,7,2,2,3,6,
%T A197518 0,1,9,0,6,3,2,7,9,1,9,7,7,9,5,3,9,2,0,1,5,0,5,3,4,0,9,4,4,3,5,6,2,7,
%U A197518 1,1,5,6,9,7,8,3,4,4,7,2,9,3,8,5,0,2,6,2,0,7,0,6,1,7,2,0,5,5,6
%N A197518 Decimal expansion of least x>0 having cos(2*Pi*x)=(cos x)^2.
%C A197518 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 A197518 This number is irrational. I cannot prove it to be algebraic or transcendental. - _Charles R Greathouse IV_, Feb 16 2025
%e A197518 0.825979156811250394882339142867223601906327919779...
%t A197518 b = 2 Pi; c = 1; f[x_] := Cos[x]
%t A197518 t = x /. FindRoot[f[b*x] == f[c*x]^2, {x, .8, .9}, WorkingPrecision -> 200]
%t A197518 RealDigits[t] (* A197518 *)
%t A197518 Plot[{f[b*x], f[c*x]^2}, {x, 0, Pi/2}]
%Y A197518 Cf. A197476.
%K A197518 nonn,cons
%O A197518 0,1
%A A197518 _Clark Kimberling_, Oct 16 2011