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

Terms

a(0) =1a(1) =5a(2) =28a(3) =21a(4) =3126a(5) =7808a(6) =823544a(7) =85a(8) =757a(9) =10003130a(10) =285311670612a(11) =256656a(13) =20661870332a(14) =2562893778a(15) =341a(17) =1898105a(19) =1290003146a(23) =8219344