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 A197477 #10 Feb 14 2025 17:38:22
%S A197477 8,4,1,8,3,5,5,3,5,6,1,4,3,6,3,8,0,7,4,8,5,7,3,2,6,7,6,5,6,2,1,6,4,3,
%T A197477 0,7,6,5,3,5,8,5,7,8,5,5,3,3,9,3,6,3,3,0,6,4,3,9,5,3,0,8,4,2,8,3,1,2,
%U A197477 0,2,8,3,2,1,4,7,6,8,9,1,4,5,1,4,8,3,3,7,8,4,4,7,7,7,4,5,5,5,9
%N A197477 Decimal expansion of least x>0 having cos(x)=(cos 3x)^2.
%C A197477 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 A197477 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>.
%e A197477 0.8418355356143638074857326765621643076...
%t A197477 b = 1; c = 3; f[x_] := Cos[x]
%t A197477 t = x /. FindRoot[f[b*x] == f[c*x]^2, {x, .8, .9}, WorkingPrecision -> 200]
%t A197477 RealDigits[t] (* A197477 *)
%t A197477 Plot[{f[b*x], f[c*x]^2}, {x, 0, Pi/2}]
%t A197477 RealDigits[ ArcCos[ Root[ 1 - 8# - 8#^2 + 16#^3 + 16#^4 &, 2]], 10, 99] // First (* _Jean-François Alcover_, Feb 19 2013 *)
%Y A197477 Cf. A197476.
%K A197477 nonn,cons
%O A197477 0,1
%A A197477 _Clark Kimberling_, Oct 15 2011