OFFSET
1,2
COMMENTS
The reduced fractions are the Farey fractions of order n (A005728). - Robert G. Wilson v, Aug 30 2010
FORMULA
For p prime, a(p) = a(p-1) + P(p) - 1, where P is the partition function (A000041).
EXAMPLE
a(3) = 4; 1 = 1/1 = 1/2 + 1/2 = 2/3 + 1/3 = 1/3 + 1/3 + 1/3.
MATHEMATICA
Farey[n_] := Union@ Flatten@ Table[a/b, {b, n}, {a, b}]; f[n_] := Length@ IntegerPartitions[1, All, Farey@ n]; Array[f, 27] (* Robert G. Wilson v, Aug 30 2010 *)
CROSSREFS
KEYWORD
more,nonn
AUTHOR
Franklin T. Adams-Watters, Aug 01 2006
EXTENSIONS
Definition corrected by Reinhard Zumkeller, Jan 17 2009
a(21) - a(27) from Robert G. Wilson v, Aug 30 2010
STATUS
approved