a(n) = (6*n + 5)^3.

Terms

a(0) =125a(1) =1331a(2) =4913a(3) =12167a(4) =24389a(5) =42875a(6) =68921a(7) =103823a(8) =148877a(9) =205379a(10) =274625a(11) =357911a(12) =456533a(13) =571787a(14) =704969a(15) =857375a(16) =1030301a(17) =1225043a(18) =1442897a(19) =1685159a(20) =1953125a(21) =2248091a(22) =2571353a(23) =2924207a(24) =3307949