A073578 a(n) = Sum_{k=1..n} mu(2*k).

-1, -1, 0, 0, 1, 1, 2, 2, 2, 2, 3, 3, 4, 4, 3, 3, 4, 4, 5, 5, 4, 4, 5, 5, 5, 5, 5, 5, 6, 6, 7, 7, 6, 6, 5, 5, 6, 6, 5, 5, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 7, 7, 8, 8, 7, 7, 6, 6, 7, 7, 8, 8, 8, 8, 7, 7, 8, 8, 7, 7, 8, 8, 9, 9, 9, 9, 8, 8, 9, 9, 9, 9, 10, 10, 9, 9, 8, 8, 9, 9, 8, 8, 7, 7, 6, 6, 7, 7, 7, 7, 8, 8, 9, 9

Offset

1,7

Comments

After a(2)=-1, the next negative value is a(8511)=-1.

Observation: It seems that Sum_{k=1..n} a(k) is usually close to n*log(n)*log(log(n)). Is Sum_{k=1..n} a(k) asymptotic to C*n*log(n)*log(log(n)) for some C near 1?

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Mathematica

Accumulate[MoebiusMu[2Range[110]]] (* Harvey P. Dale, Apr 30 2012 *)

Crossrefs

Cf. A008683.

Sequence in context: A064658 A194292 A308403 * A087866 A061392 A048273

Adjacent sequences: A073575 A073576 A073577 * A073579 A073580 A073581

Keyword

easy,sign

Author

Benoit Cloitre, Aug 28 2002

Extensions

Edited by Dean Hickerson, Sep 04 2002

Status

approved