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 A199740 #13 Feb 08 2025 22:25:30
%S A199740 1,2,7,3,0,8,0,7,1,4,9,0,1,0,1,5,3,5,9,2,5,0,2,7,2,7,8,3,1,5,1,9,3,1,
%T A199740 8,9,0,6,6,8,3,2,5,7,2,2,2,0,8,4,0,8,0,9,8,9,7,0,7,5,2,5,0,5,4,1,1,7,
%U A199740 3,9,5,0,4,6,9,5,9,7,1,1,5,0,7,2,8,6,7,7,2,1,6,8,7,1,1,5,5,0,4
%N A199740 Decimal expansion of x>0 satisfying 2*x^2-x*cos(x)=3*sin(x).
%C A199740 See A199597 for a guide to related sequences. The Mathematica program includes a graph.
%H A199740 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>.
%e A199740 1.27308071490101535925027278315193189066832...
%t A199740 a = 2; b = -1; c = 3;
%t A199740 f[x_] := a*x^2 + b*x*Cos[x]; g[x_] := c*Sin[x]
%t A199740 Plot[{f[x], g[x]}, {x, -1, 2}, {AxesOrigin -> {0, 0}}]
%t A199740 r = x /. FindRoot[f[x] == g[x], {x, 1.27, 1.28}, WorkingPrecision -> 110]
%t A199740 RealDigits[r] (* A199740 *)
%Y A199740 Cf. A199597.
%K A199740 nonn,cons
%O A199740 1,2
%A A199740 _Clark Kimberling_, Nov 10 2011
%E A199740 Name corrected by _Sean A. Irvine_, Jan 12 2025