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 A049806 #11 Sep 25 2018 12:20:02
%S A049806 1,2,3,4,6,7,10,12,15,17,22,24,30,33,37,41,49,52,61,65,71,76,87,91,
%T A049806 101,107,116,122,136,140,155,163,173,181,193,199,217,226,238,246,266,
%U A049806 272,293,303,315,326,349,357,378,388,404,416,442
%N A049806 Number of Farey fractions of order n that are <=1/2; cf. A049805.
%t A049806 Farey[n_] := Union[Flatten[Join[{0}, Table[a/b, {b, n}, {a, b}]]]]; f[n_] := Length@ Select[ Farey@ n, # <= 1/2 &]; Array[f, 53] (* _Robert G. Wilson v_, Nov 14 2012 *)
%t A049806 a[n_] := Count[FareySequence[n], f_ /; f <= 1/2]; Array[a, 53] (* _Jean-François Alcover_, Sep 25 2018 *)
%Y A049806 Partial sums + 1 of A023022.
%Y A049806 Cf. A005728, A049807, A049808, A049809, A049810, A049811, A049812, A049813, A049814.
%K A049806 nonn
%O A049806 1,2
%A A049806 _Clark Kimberling_