a(n) = Sum_{p|n, p prime} p^sigma(n/p).

Terms

a(0) =0a(1) =2a(2) =3a(3) =8a(4) =5a(5) =43a(6) =7a(7) =128a(8) =81a(9) =189a(10) =11a(11) =6283a(12) =13a(13) =599a(14) =1354a(15) =32768a(16) =17a(17) =539633a(18) =19a(19) =340269a(20) =8962a(21) =5427a(22) =23a(23) =282784363a(24) =15625a(25) =18581a(26) =1594323a(27) =17600759a(28) =29a(29) =648338330