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

Terms

a(0) =1a(1) =3a(2) =4a(3) =7a(4) =6a(5) =14a(6) =8a(7) =17a(8) =19a(9) =32a(10) =12a(11) =48a(12) =14a(13) =86a(14) =122a(15) =57a(16) =18a(17) =137a(18) =20a(19) =328a(20) =800a(21) =1058a(22) =24a(23) =250a(24) =651a(25) =4136a(26) =838a(27) =4252a(28) =30a(29) =1804