OFFSET
1,1
COMMENTS
Note that a(n) = 0 for even n and a(n) = n-2 for prime n. It appears that the following are true: a(1) is the only positive even term, all odd numbers eventually appear in the sequence, a(n) = 0 if n is squareful and a(n) > 0 if n is squarefree. Assuming the truth of the last statement, we can show that if distinct odd primes p and q divide n, then A051664(n) > p + q - 2.
LINKS
T. D. Noe, Table of n, a(n) for n=1..1000
FORMULA
a(n) = Sum{d|n} mu(n/d) A051664(d)
CROSSREFS
KEYWORD
nonn
AUTHOR
T. D. Noe, Aug 08 2003
EXTENSIONS
Definition corrected: "inverse moebius transform" to "moebius transform" by Wouter Meeussen, Jan 17 2009
STATUS
approved