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 A199439 #9 Feb 07 2025 23:37:06
%S A199439 7,1,8,5,2,7,1,4,8,7,1,1,1,8,8,8,2,1,1,4,5,3,1,2,5,7,9,7,1,8,2,6,8,8,
%T A199439 4,7,6,3,1,0,1,6,9,4,2,9,3,9,1,3,0,8,5,1,0,4,8,5,2,5,6,4,0,5,7,1,5,5,
%U A199439 6,0,6,3,8,0,0,9,5,5,5,5,9,1,5,1,2,3,8,8,4,6,9,0,7,1,0,9,5,2,9
%N A199439 Decimal expansion of x>0 satisfying 2*x^2+x*sin(x)=2*cos(x).
%C A199439 See A199370 for a guide to related sequences. The Mathematica program includes a graph.
%H A199439 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>.
%e A199439 0.718527148711188821145312579718268847631016...
%t A199439 a = 2; b = 1; c = 2;
%t A199439 f[x_] := a*x^2 + b*x*Sin[x]; g[x_] := c*Cos[x]
%t A199439 Plot[{f[x], g[x]}, {x, -Pi, Pi}, {AxesOrigin -> {0, 0}}]
%t A199439 r = x /. FindRoot[f[x] == g[x], {x, .71, .72}, WorkingPrecision -> 110]
%t A199439 RealDigits[r] (* A199439 *)
%Y A199439 Cf. A199429.
%K A199439 nonn,cons
%O A199439 0,1
%A A199439 _Clark Kimberling_, Nov 06 2011