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 A197478 #7 Feb 14 2025 17:38:25
%S A197478 6,6,5,3,7,5,3,1,9,8,2,0,6,9,4,5,9,9,9,4,1,0,9,7,6,2,4,1,4,1,6,9,7,3,
%T A197478 2,1,2,9,4,4,4,0,0,4,9,3,7,5,9,6,0,2,5,5,6,0,6,2,0,9,0,9,6,7,4,4,0,1,
%U A197478 3,1,7,1,1,4,8,5,3,7,9,5,5,8,6,5,1,2,8,2,4,6,6,5,1,3,5,5,6,3,9
%N A197478 Decimal expansion of least x>0 having cos(x)=(cos 4x)^2.
%C A197478 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.
%H A197478 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>.
%e A197478 0.6653753198206945999410976241416973212944400...
%t A197478 b = 1; c = 4; f[x_] := Cos[x]
%t A197478 t = x /. FindRoot[f[b*x] == f[c*x]^2, {x, .6, .7}, WorkingPrecision -> 200]
%t A197478 RealDigits[t] (* A197478 *)
%t A197478 Plot[{f[b*x], f[c*x]^2}, {x, 0, 1}]
%Y A197478 Cf. A197476.
%K A197478 nonn,cons
%O A197478 0,1
%A A197478 _Clark Kimberling_, Oct 15 2011