a(n) = (n^3 - 1)^3.

Terms

a(0) =0a(1) =343a(2) =17576a(3) =250047a(4) =1906624a(5) =9938375a(6) =40001688a(7) =133432831a(8) =385828352a(9) =997002999a(10) =2352637000a(11) =5150827583a(12) =10590025536a(13) =20638466407a(14) =38409197624a(15) =68669157375a(16) =118515478528a(17) =198257271191a(18) =322546580712a(19) =511808023999