login
A105590
a(n)=n+2-sum{k=0..n, -mu(k-mod(k^3,3k))}
0
1, 1, 1, 1, 1, 1, 3, 3, 3, 4, 4, 4, 5, 5, 5, 7, 7, 7, 8, 8, 8, 10, 10, 10, 11, 11, 11, 12, 12, 12, 12, 12, 12, 14, 14, 14, 15, 15, 15, 17, 17, 17, 17, 17, 17, 18, 18, 18, 19, 19, 19, 21, 21, 21, 22, 22, 22, 24, 24, 24, 25, 25, 25, 26, 26, 26, 26, 26, 26, 28, 28, 28, 29, 29, 29, 30
OFFSET
0,7
COMMENTS
A Moebius triple count.
Numbers appear in triples or multiples of triples.
CROSSREFS
Sequence in context: A096056 A050501 A327469 * A220845 A361469 A073750
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Apr 14 2005
STATUS
approved