a(n) = Sum_{d divides n} d*(n/d)^(d-1).

Terms

a(0) =1a(1) =3a(2) =4a(3) =9a(4) =6a(5) =25a(6) =8a(7) =49a(8) =37a(9) =101a(10) =12a(11) =373a(12) =14a(13) =477a(14) =496a(15) =1313a(16) =18a(17) =3907a(18) =20a(19) =6941a(20) =5272a(21) =11309a(22) =24a(23) =49321a(24) =3151a(25) =53301a(26) =59320a(27) =144789a(28) =30a(29) =468181