Squares and cubes.

Terms

a(0) =0a(1) =1a(2) =4a(3) =8a(4) =9a(5) =16a(6) =25a(7) =27a(8) =36a(9) =49a(10) =64a(11) =81a(12) =100a(13) =121a(14) =125a(15) =144a(16) =169a(17) =196a(18) =216a(19) =225a(20) =256a(21) =289a(22) =324a(23) =343a(24) =361a(25) =400a(26) =441a(27) =484a(28) =512a(29) =529