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A062563
a(n) = Sum_{k=1..n} d(k)* mu(k), where d(k) is the number of divisors function.
1
1, -1, -3, -3, -5, -1, -3, -3, -3, 1, -1, -1, -3, 1, 5, 5, 3, 3, 1, 1, 5, 9, 7, 7, 7, 11, 11, 11, 9, 1, -1, -1, 3, 7, 11, 11, 9, 13, 17, 17, 15, 7, 5, 5, 5, 9, 7, 7, 7, 7, 11, 11, 9, 9, 13, 13, 17, 21, 19, 19, 17, 21, 21, 21, 25, 17, 15, 15, 19, 11, 9, 9, 7, 11, 11, 11, 15, 7, 5, 5, 5, 9, 7, 7, 11, 15, 19, 19, 17, 17, 21, 21, 25, 29, 33, 33, 31
OFFSET
1,3
FORMULA
Also a(n) = Sum_{k=1..n} 2^omega(k)*mu(k). - Benoit Cloitre, Jun 13 2007
MATHEMATICA
Accumulate[Table[DivisorSigma[0, n]MoebiusMu[n], {n, 100}]] (* Harvey P. Dale, Aug 15 2016 *)
PROG
(PARI) v=[]; for(n=1, 250, v=concat(v, sum(k=1, n, numdiv(k)*moebius(k)))); v
CROSSREFS
Partial sums of A226177.
Sequence in context: A320298 A021753 A353412 * A091931 A109824 A011399
KEYWORD
sign
AUTHOR
Jason Earls, Jul 03 2001
STATUS
approved