A105590 a(n)=n+2-sum{k=0..n, -mu(k-mod(k^3,3k))}

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.

Links

Table of n, a(n) for n=0..75.

Crossrefs

Sequence in context: A096056 A050501 A327469 * A220845 A361469 A073750

Adjacent sequences: A105587 A105588 A105589 * A105591 A105592 A105593

Keyword

easy,nonn

Author

Paul Barry, Apr 14 2005

Status

approved