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 A197516 #7 Feb 16 2025 05:30:36
%S A197516 1,7,9,8,5,9,1,0,3,7,0,2,8,6,9,8,4,4,2,7,7,5,5,7,2,9,2,8,4,5,2,1,6,1,
%T A197516 3,1,1,7,0,8,8,7,0,5,1,1,1,7,5,7,5,5,6,1,5,0,4,0,8,7,1,5,6,4,2,6,4,7,
%U A197516 6,4,6,4,9,7,8,2,0,0,6,9,9,0,1,9,0,4,3,4,6,4,0,4,9,1,3,8,5,3,2
%N A197516 Decimal expansion of least x>0 having cos(Pi*x)=(cos 2x)^2.
%C A197516 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 A197516 This number is irrational. I cannot prove it to be algebraic or transcendental. - _Charles R Greathouse IV_, Feb 16 2025
%e A197516 1.79859103702869844277557292845216131170...
%t A197516 b = Pi; c = 2; f[x_] := Cos[x]
%t A197516 t = x /. FindRoot[f[b*x] == f[c*x]^2, {x, 1.7, 1.8}, WorkingPrecision -> 200]
%t A197516 RealDigits[t] (* A197516 *)
%t A197516 Plot[{f[b*x], f[c*x]^2}, {x, 0, 3}]
%Y A197516 Cf. A197476.
%K A197516 nonn,cons
%O A197516 1,2
%A A197516 _Clark Kimberling_, Oct 16 2011