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

Terms

a(0) =0a(1) =1a(2) =2a(3) =7a(4) =4a(5) =30a(6) =6a(7) =107a(8) =44a(9) =98a(10) =10a(11) =2000a(12) =12a(13) =206a(14) =258a(15) =6035a(16) =16a(17) =21963a(18) =18a(19) =14664a(20) =540a(21) =542a(22) =22a(23) =3165444a(24) =424a(25) =770a(26) =6434a(27) =53384a(28) =28a(29) =544568