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 A199438 #8 Feb 07 2025 20:10:54
%S A199438 5,3,9,1,4,3,6,0,7,0,3,1,4,0,4,1,0,6,4,8,7,9,4,6,0,7,0,9,9,5,5,2,3,7,
%T A199438 2,1,2,7,0,6,0,6,8,1,4,6,9,8,9,7,5,3,8,4,0,5,8,1,4,4,5,3,7,7,4,9,3,8,
%U A199438 0,5,3,0,3,9,4,5,6,7,7,4,0,0,7,3,5,7,8,1,4,2,0,5,3,3,4,9,7,1,6
%N A199438 Decimal expansion of x>0 satisfying 2*x^2+x*sin(x)=cos(x).
%C A199438 See A199370 for a guide to related sequences. The Mathematica program includes a graph.
%H A199438 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>.
%e A199438 0.539143607031404106487946070995523721270...
%t A199438 a = 2; b = 1; c = 1;
%t A199438 f[x_] := a*x^2 + b*x*Sin[x]; g[x_] := c*Cos[x]
%t A199438 Plot[{f[x], g[x]}, {x, -Pi, Pi}, {AxesOrigin -> {0, 0}}]
%t A199438 r = x /. FindRoot[f[x] == g[x], {x, .53, .54}, WorkingPrecision -> 110]
%t A199438 RealDigits[r] (* A199438 *)
%Y A199438 Cf. A199429.
%K A199438 nonn,cons
%O A199438 0,1
%A A199438 _Clark Kimberling_, Nov 06 2011