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 A198539 #9 Apr 23 2025 12:41:57
%S A198539 2,5,2,6,5,1,2,1,7,3,6,3,0,6,7,9,6,9,8,4,9,9,4,7,8,9,1,4,6,7,0,0,1,5,
%T A198539 8,8,9,4,0,1,1,1,8,9,2,5,4,4,2,2,4,9,7,2,1,6,2,5,7,7,4,4,6,8,3,0,5,9,
%U A198539 7,5,5,7,0,4,8,0,1,9,1,4,6,5,2,5,6,0,8,5,7,8,4,5,2,1,2,5,6,0,9
%N A198539 Decimal expansion of x<0 having 4*x^2+2x=sin(x).
%C A198539 See A198414 for a guide to related sequences. The Mathematica program includes a graph.
%H A198539 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>.
%e A198539 -0.252651217363067969849947891467001...
%t A198539 a = 4; b = 2; c = 1;
%t A198539 f[x_] := a*x^2 + b*x; g[x_] := c*Sin[x]
%t A198539 Plot[{f[x], g[x]}, {x, -.6, .2}]
%t A198539 r = x /. FindRoot[f[x] == g[x], {x, -.26, -.25}, WorkingPrecision -> 110]
%t A198539 RealDigits[r] (* A198539 *)
%Y A198539 Cf. A198414.
%K A198539 nonn,cons
%O A198539 0,1
%A A198539 _Clark Kimberling_, Oct 26 2011