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 A198108 #8 Feb 07 2025 16:44:04
%S A198108 2,0,7,2,1,9,1,3,0,2,7,1,1,8,0,9,3,2,7,3,7,9,6,8,2,2,9,0,0,2,7,0,0,3,
%T A198108 7,2,6,5,6,8,7,2,0,3,7,5,9,3,5,8,9,1,6,2,5,2,8,7,0,1,4,3,3,8,1,2,1,1,
%U A198108 8,3,7,7,0,3,9,0,6,6,3,2,8,1,3,6,2,5,0,3,7,1,3,0,1,2,0,7,1,5,7
%N A198108 Decimal expansion of least x having x^2+3x=4*cos(x).
%C A198108 See A197737 for a guide to related sequences. The Mathematica program includes a graph.
%e A198108 least x: -2.072191302711809327379682290027003...
%e A198108 greatest x: 0.7657264429205407174831010492394...
%t A198108 a = 1; b = 3; c = 4;
%t A198108 f[x_] := a*x^2 + b*x; g[x_] := c*Cos[x]
%t A198108 Plot[{f[x], g[x]}, {x, -3, 1}]
%t A198108 r1 = x /. FindRoot[f[x] == g[x], {x, -2.1, -2.9}, WorkingPrecision -> 110]
%t A198108 RealDigits[r1] (* A198108 *)
%t A198108 r2 = x /. FindRoot[f[x] == g[x], {x, .76, .77}, WorkingPrecision -> 110]
%t A198108 RealDigits[r2] (* A198109 *)
%Y A198108 Cf. A197737.
%K A198108 nonn,cons
%O A198108 1,1
%A A198108 _Clark Kimberling_, Oct 21 2011