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 A198126 #6 Feb 07 2025 16:44:04
%S A198126 1,3,0,3,6,8,8,2,3,6,0,8,2,7,3,1,2,3,6,1,5,7,9,4,2,3,4,9,2,0,1,7,3,1,
%T A198126 5,8,1,7,1,3,6,6,2,5,6,7,7,7,5,0,6,2,3,8,8,1,7,3,8,3,0,4,5,9,1,1,6,0,
%U A198126 2,7,0,3,4,3,4,5,4,9,4,8,7,8,0,3,8,4,4,5,0,8,7,1,0,4,7,6,8,2,1
%N A198126 Decimal expansion of least x having 2*x^2+2x=3*cos(x).
%C A198126 See A197737 for a guide to related sequences. The Mathematica program includes a graph.
%e A198126 least x: -1.303688236082731236157942349201731581...
%e A198126 greatest x: 0.68722829225254885401536676699761905...
%t A198126 a = 2; b = 2; c = 3;
%t A198126 f[x_] := a*x^2 + b*x; g[x_] := c*Cos[x]
%t A198126 Plot[{f[x], g[x]}, {x, -2, 1}]
%t A198126 r1 = x /. FindRoot[f[x] == g[x], {x, -1.31, -1.30}, WorkingPrecision -> 110]
%t A198126 RealDigits[r1] (* A198126 *)
%t A198126 r2 = x /. FindRoot[f[x] == g[x], {x, .68, .69}, WorkingPrecision -> 110]
%t A198126 RealDigits[r2] (* A198127 *)
%Y A198126 Cf. A197737.
%K A198126 nonn,cons
%O A198126 1,2
%A A198126 _Clark Kimberling_, Oct 22 2011