A049812 a(n)=number of Farey fractions of order n that are <=1/8; cf. A049805.

1, 1, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 13, 15, 16, 18, 19, 21, 22, 25, 27, 29, 31, 34, 35, 38, 40, 43, 45, 49, 50, 54, 56, 59, 61, 66, 68, 73, 76, 79, 82, 87, 89, 95, 97, 101, 104, 110, 112, 117, 120, 125, 129, 136, 138

Offset

1,8

Links

Table of n, a(n) for n=1..60.

Mathematica

Farey[n_] := Union[Flatten[Join[{0}, Table[a/b, {b, n}, {a, b}]]]]; f[n_] := Length@ Select[ Farey@ n, # <= 1/8 &]; Array[f, 60] (* Robert G. Wilson v, Nov 14 2012 *)

Crossrefs

Cf. A005728, A049806, A049807, A049808, A049809, A049810, A049811, A049813, A049814.

Sequence in context: A309129 A307345 A033110 * A093668 A026501 A000926

Adjacent sequences: A049809 A049810 A049811 * A049813 A049814 A049815

Keyword

nonn

Author

Clark Kimberling

Status

approved