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 A196822 #12 Aug 10 2021 21:41:59
%S A196822 6,8,6,9,2,8,0,7,2,5,0,7,1,1,4,1,5,1,4,7,7,4,2,6,6,1,4,9,4,4,4,5,7,6,
%T A196822 9,5,9,5,8,2,2,1,4,9,8,9,9,9,1,3,4,9,6,4,8,4,9,0,6,0,3,7,4,0,8,8,7,4,
%U A196822 9,3,4,1,8,8,9,1,8,1,0,9,4,8,5,5,2,9,3,5,1,3,7,4,0,6,3,2,1,4,1,2,1,6,8,8,9,8
%N A196822 Decimal expansion of the number x satisfying 2*x = ((1+x^2)^2)*sin(x) and 0 < x < 2*Pi.
%e A196822 x=0.686928072507114151477426614944457695958221498999...
%t A196822 Plot[{1/(1 + x^2), -.097 + Cos[x]}, {x, 0, 1}]
%t A196822 t = x /. FindRoot[2 x == ((1 + x^2)^2) Sin[x], {x, .5, 1}, WorkingPrecision -> 100]
%t A196822 RealDigits[t] (* A196822 *)
%t A196822 c = N[-Cos[t] + 1/(1 + t^2), 100]
%t A196822 RealDigits[c] (* A196823 *)
%t A196822 slope = N[-Sin[t], 100]
%t A196822 RealDigits[slope] (* A196824 *)
%Y A196822 Cf. A196823.
%K A196822 nonn,cons
%O A196822 0,1
%A A196822 _Clark Kimberling_, Oct 06 2011
%E A196822 Definition and a(84) onwards corrected by _Georg Fischer_, Aug 10 2021