OFFSET
1,1
LINKS
FORMULA
Asymptotically: Sum_{k=1..n} a(k) = 2*C*n*log(n) + O(n*log(n)) with C = 1.1...
MATHEMATICA
a[n_] := 2 * DivisorSum[n, 2^MoebiusMu[#] &]; Array[a, 100] (* Amiram Eldar, Jun 04 2022 *)
PROG
(PARI) for(n=1, 100, print1(2*sumdiv(n, d, 2^moebius(d)), ", "))
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Benoit Cloitre, May 31 2002
STATUS
approved