a(n) = p^3*(p-1), where p = prime(n).

Terms

a(0) =8a(1) =54a(2) =500a(3) =2058a(4) =13310a(5) =26364a(6) =78608a(7) =123462a(8) =267674a(9) =682892a(10) =893730a(11) =1823508a(12) =2756840a(13) =3339294a(14) =4775858a(15) =7741604a(16) =11911982a(17) =13618860a(18) =19850358a(19) =25053770a(20) =28009224a(21) =38457042a(22) =46886534a(23) =62037272a(24) =87616608a(25) =103030100a(26) =111458154