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%I #8 Nov 14 2012 10:12:29
%S 1,1,2,3,4,5,7,8,10,12,15,16,20,22,25,28,33,35,41,43,47,51,58,61,68,
%T 72,78,82,91,93,103,108,115,121,129,133,145,151,159,165,178,182,196,
%U 202,210,218,233,238,252,258,269,277,294,300
%N a(n)=number of Farey fractions of order n that are <=1/3; cf. A049805.
%t Farey[n_] := Union[Flatten[Join[{0}, Table[a/b, {b, n}, {a, b}]]]]; f[n_] := Length@ Select[ Farey@ n, # <= 1/3 &]; Array[f, 54] (* _Robert G. Wilson v_, Nov 14 2012 *)
%Y Cf. A005728, A049806, A049808, A049809, A049810, A049811, A049812, A049813, A049814.
%K nonn
%O 1,3
%A _Clark Kimberling_