a(n) = n^4 * Sum_{p|n, p prime} 1/p^4.

Terms

a(0) =0a(1) =1a(2) =1a(3) =16a(4) =1a(5) =97a(6) =1a(7) =256a(8) =81a(9) =641a(10) =1a(11) =1552a(12) =1a(13) =2417a(14) =706a(15) =4096a(16) =1a(17) =7857a(18) =1a(19) =10256a(20) =2482a(21) =14657a(22) =1a(23) =24832a(24) =625a(25) =28577a(26) =6561a(27) =38672a(28) =1a(29) =61921