Perfect powers: m^k where m > 0 and k >= 2.

Terms

a(0) =1a(1) =4a(2) =8a(3) =9a(4) =16a(5) =25a(6) =27a(7) =32a(8) =36a(9) =49a(10) =64a(11) =81a(12) =100a(13) =121a(14) =125a(15) =128a(16) =144a(17) =169a(18) =196a(19) =216a(20) =225a(21) =243a(22) =256a(23) =289a(24) =324a(25) =343a(26) =361a(27) =400a(28) =441a(29) =484