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 A049809 #8 Nov 14 2012 10:12:15
%S A049809 1,1,1,1,2,3,4,5,6,7,9,10,12,13,15,17,20,21,24,26,29,31,35,36,40,43,
%T A049809 47,50,55,56,62,65,69,72,77,80,87,91,96,99,107,109,117,121,126,131,
%U A049809 140,143,151,155,162,167,177,180,188,193,201,207
%N A049809 a(n)=number of Farey fractions of order n that are <=1/5; cf. A049805.
%t A049809 Farey[n_] := Union[Flatten[Join[{0}, Table[a/b, {b, n}, {a, b}]]]]; f[n_] := Length@ Select[ Farey@ n, # <= 1/5 &]; Array[f, 58] (* _Robert G. Wilson v_, Nov 14 2012 *)
%Y A049809 Cf. A005728, A049806, A049807, A049808, A049810, A049811, A049812, A049813, A049814.
%K A049809 nonn
%O A049809 1,5
%A A049809 _Clark Kimberling_