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 A198134 #11 Apr 10 2025 06:51:12
%S A198134 1,5,3,9,9,9,5,2,2,7,2,6,6,8,3,9,0,8,1,8,0,5,9,8,8,5,8,0,2,0,4,0,5,4,
%T A198134 2,5,3,5,5,4,3,3,5,8,2,9,2,4,3,1,7,9,4,9,6,0,9,4,6,6,9,4,6,6,3,8,4,5,
%U A198134 0,1,2,5,0,3,2,8,3,5,1,3,8,9,7,0,5,5,5,3,7,9,3,3,0,0,3,6,7,1,9
%N A198134 Decimal expansion of least x having 2*x^2+3x=4*cos(x).
%C A198134 See A197737 for a guide to related sequences. The Mathematica program includes a graph.
%e A198134 Least x: -1.5399952272668390818059885802040...
%e A198134 Greatest x: 0.6975345552284129937951740662521298...
%t A198134 a = 2; b = 3; c = 4;
%t A198134 f[x_] := a*x^2 + b*x; g[x_] := c*Cos[x]
%t A198134 Plot[{f[x], g[x]}, {x, -2, 1}]
%t A198134 r1 = x /. FindRoot[f[x] == g[x], {x, -1.54, -1.539}, WorkingPrecision -> 110]
%t A198134 RealDigits[r1] (* A198134 *)
%t A198134 r2 = x /. FindRoot[f[x] == g[x], {x, .79, .70}, WorkingPrecision -> 110]
%t A198134 RealDigits[r2] (* A198135 *)
%Y A198134 Cf. A197737.
%K A198134 nonn,cons
%O A198134 1,2
%A A198134 _Clark Kimberling_, Oct 22 2011