OFFSET
1,1
COMMENTS
It appears that this equals A200511, numbers of the form p^k q^m with k,m >= 1, k+m > 2 and p, q prime. - M. F. Hasler, Feb 12 2012
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..1000
MATHEMATICA
Moebius[i_, j_] := If[Divisible[i, j], MoebiusMu[i/j], 0]; A123709[n_] :=
Length[Select[Table[Moebius[n, j] - Moebius[n, j + 1], {j, 1, n}], # != 0 &]]; Select[Range[500], A123709[#] == 8 &] (* G. C. Greubel, Apr 22 2017 *)
PROG
(PARI)
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Oct 09 2006
STATUS
approved