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A049813 a(n)=number of Farey fractions of order n that are <=1/9; cf. A049805. 8
1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 16, 17, 19, 20, 22, 23, 25, 27, 30, 31, 34, 36, 38, 40, 43, 44, 48, 50, 53, 55, 59, 60, 64, 66, 69, 72, 77, 79, 84, 86, 90, 93, 98, 100, 105, 108, 112, 115, 121, 122 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,9
LINKS
MATHEMATICA
Farey[n_] := Union[Flatten[Join[{0}, Table[a/b, {b, n}, {a, b}]]]]; f[n_] := Length@ Select[ Farey@ n, # <= 1/9 &]; Array[f, 60] (* Robert G. Wilson v, Nov 14 2012 *)
CROSSREFS
Sequence in context: A354928 A195044 A033112 * A354925 A362184 A368904
KEYWORD
nonn
AUTHOR
STATUS
approved

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Last modified February 22 02:45 EST 2024. Contains 370239 sequences. (Running on oeis4.)