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 A197515 #7 Feb 16 2025 05:30:38
%S A197515 1,5,0,1,5,2,4,9,8,0,4,5,5,7,6,2,5,5,0,6,8,3,9,4,7,2,6,2,8,8,6,2,7,8,
%T A197515 1,5,7,1,3,6,5,1,4,4,5,3,0,7,2,3,4,1,1,2,5,6,3,8,4,9,9,4,4,2,6,0,3,3,
%U A197515 6,3,3,7,7,9,5,5,4,5,0,0,8,4,2,8,5,0,5,8,5,0,5,1,3,5,3,6,6,8,3
%N A197515 Decimal expansion of least x>0 having cos(Pi*x)=(cos x)^2.
%C A197515 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 A197515 This number is irrational. I cannot prove it to be algebraic or transcendental. - _Charles R Greathouse IV_, Feb 16 2025
%e A197515 1.501524980455762550683947262886278157...
%t A197515 b = Pi; c = 1; f[x_] := Cos[x]
%t A197515 t = x /. FindRoot[f[b*x] == f[c*x]^2, {x, 1.5, 1.502},
%t A197515 WorkingPrecision -> 200]
%t A197515 RealDigits[t] (* A197515 *)
%t A197515 Plot[{f[b*x], f[c*x]^2}, {x, 0, 3}]
%Y A197515 Cf. A197476.
%K A197515 nonn,cons
%O A197515 1,2
%A A197515 _Clark Kimberling_, Oct 16 2011