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

Terms

a(0) =1a(1) =4a(2) =6a(3) =16a(4) =10a(5) =54a(6) =14a(7) =112a(8) =99a(9) =230a(10) =22a(11) =996a(12) =26a(13) =1022a(14) =1620a(15) =3232a(16) =34a(17) =9828a(18) =38a(19) =18100a(20) =16380a(21) =22814a(22) =46a(23) =133272a(24) =15675a(25) =106886a(26) =179388a(27) =354116a(28) =58a(29) =1218150