a(n) = Sum_{d|n} d^(tau(d) - 1).

Terms

a(0) =1a(1) =3a(2) =4a(3) =19a(4) =6a(5) =222a(6) =8a(7) =531a(8) =85a(9) =1008a(10) =12a(11) =249070a(12) =14a(13) =2754a(14) =3384a(15) =66067a(16) =18a(17) =1889871a(18) =20a(19) =3201024a(20) =9272a(21) =10662a(22) =24a(23) =4586721006a(24) =631a(25) =17592a(26) =19768a(27) =17213138a(28) =30a(29) =21870004602