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 A196503 #9 Jul 10 2019 01:49:50
%S A196503 2,0,3,5,3,4,1,4,9,0,7,6,5,6,4,4,3,9,6,9,7,5,7,4,2,2,2,3,9,7,3,9,5,2,
%T A196503 9,0,2,8,9,9,9,6,9,4,1,3,1,7,8,0,3,3,8,0,9,8,1,7,6,3,5,9,4,1,3,1,0,1,
%U A196503 4,6,0,9,4,3,1,2,7,3,6,8,5,8,3,7,8,4,9,4,3,1,4,3,2,4,1,7,7,1,1,2
%N A196503 Decimal expansion of greatest x satisfying cos(x)=1/sqrt(1+x^2).
%C A196503 See A196502 and A196500 for related inequalities.
%e A196503 x=0.203534149076564439697574222397395290289996941...
%t A196503 Plot[{Cos[x], 1/Sqrt[1 + x^2]}, {x, 0, 8}]
%t A196503 t = x /.FindRoot[1/Sqrt[1 + x^2] == Cos[x], {x, 4, 5}, WorkingPrecision -> 100]
%t A196503 RealDigits[t] (* A196502 *)
%t A196503 1/t
%t A196503 RealDigits[1/t] (* A196503 *)
%Y A196503 Cf. A196500, A196502, A196504.
%K A196503 nonn,cons
%O A196503 0,1
%A A196503 _Clark Kimberling_, Oct 03 2011