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

Terms

a(0) =1a(1) =3a(2) =10a(3) =19a(4) =626a(5) =48a(6) =117650a(7) =4115a(8) =531451a(9) =10628a(10) =25937424602a(11) =20800a(13) =7647188a(14) =2562891260a(15) =4294971411a(17) =34543713a(19) =25600010644