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 A198142 #6 Feb 07 2025 16:44:05
%S A198142 8,9,2,9,1,0,7,1,1,4,1,7,7,7,5,2,7,3,7,3,9,9,6,8,3,1,8,3,1,7,0,4,5,6,
%T A198142 9,8,6,9,3,9,7,7,5,0,3,1,2,4,3,6,6,5,2,2,8,2,9,0,2,9,8,6,4,1,2,7,0,7,
%U A198142 0,4,6,7,0,0,5,0,2,4,0,7,4,7,2,4,8,9,6,6,3,4,0,7,0,3,0,0,6,9,3
%N A198142 Decimal expansion of least x having x^2-3x=-3*cos(x).
%C A198142 See A197737 for a guide to related sequences. The Mathematica program includes a graph.
%e A198142 least x: 0.89291071141777527373996831831704569...
%e A198142 greatest x: 3.6923477739279898601828477062994010...
%t A198142 a = 1; b = -3; c = -3;
%t A198142 f[x_] := a*x^2 + b*x; g[x_] := c*Cos[x]
%t A198142 Plot[{f[x], g[x]}, {x, -1, 4}]
%t A198142 r1 = x /. FindRoot[f[x] == g[x], {x, 0.89, 0.90}, WorkingPrecision -> 110]
%t A198142 RealDigits[r1] (* A198142 *)
%t A198142 r2 = x /. FindRoot[f[x] == g[x], {x, 3.6, 3.7}, WorkingPrecision -> 110]
%t A198142 RealDigits[r2] (* A198143 *)
%Y A198142 Cf. A197737.
%K A198142 nonn,cons
%O A198142 0,1
%A A198142 _Clark Kimberling_, Oct 21 2011