a(n) = Sum_{d|n} mu(n/d)*d*sigma_n(d).

A321294

a(n) = Sum_{d|n} mu(n/d)*d*sigma_n(d).

Terms

    a(0) =1a(1) =9a(2) =83a(3) =1058a(4) =15629a(5) =282381a(6) =5764807a(7) =134480900a(8) =3486902505a(9) =100048836321

External references