sigma_3(n): sum of cubes of divisors of n.

Terms

a(0) =1a(1) =9a(2) =28a(3) =73a(4) =126a(5) =252a(6) =344a(7) =585a(8) =757a(9) =1134a(10) =1332a(11) =2044a(12) =2198a(13) =3096a(14) =3528a(15) =4681a(16) =4914a(17) =6813a(18) =6860a(19) =9198a(20) =9632a(21) =11988a(22) =12168a(23) =16380a(24) =15751a(25) =19782a(26) =20440a(27) =25112a(28) =24390a(29) =31752