A049811 a(n)=number of Farey fractions of order n that are <=1/7; cf. A049805.

1, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 14, 15, 17, 18, 20, 22, 25, 26, 29, 31, 33, 35, 39, 40, 44, 46, 49, 51, 55, 57, 62, 65, 69, 71, 76, 78, 84, 87, 90, 93, 99, 101, 107, 110, 115, 119, 126, 129, 135, 138, 144, 148, 156, 158

Offset

1,7

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, # <= 1/7 &]; Array[f, 60] (* Robert G. Wilson v, Nov 14 2012 *)

Crossrefs

Cf. A005728, A049806, A049807, A049808, A049809, A049810, A049812, A049813, A049814.

Sequence in context: A099649 A330982 A033108 * A124097 A180478 A062461

Adjacent sequences: A049808 A049809 A049810 * A049812 A049813 A049814

Keyword

nonn

Author

Clark Kimberling

Status

approved