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

Terms

a(0) =1a(1) =3a(2) =4a(3) =9a(4) =6a(5) =12a(6) =8a(7) =29a(8) =37a(9) =18a(10) =12a(11) =60a(12) =14a(13) =24a(14) =24a(15) =341a(16) =18a(17) =273a(18) =20a(19) =134a(20) =32a(21) =36a(22) =24a(23) =236a(24) =3151a(25) =42a(26) =784a(27) =240a(28) =30a(29) =72