OFFSET
0,3
MATHEMATICA
Table[Sum[MoebiusMu[k]DivisorSigma[1, k], {k, n}], {n, 0, 80}] (* Harvey P. Dale, Nov 08 2011 *)
PROG
(PARI) s=[]; for(n=0, 130, s=concat(s, sum(k=1, n, moebius(k)*sigma(k)))); s
CROSSREFS
KEYWORD
sign
AUTHOR
Jason Earls, Jul 03 2001
EXTENSIONS
Corrected by Harvey P. Dale, Nov 08 2011
STATUS
approved