Powers of 3-Step Lucas numbers (A001644).

Terms

a(0) =1a(1) =3a(2) =9a(3) =11a(4) =21a(5) =27a(6) =39a(7) =49a(8) =71a(9) =81a(10) =121a(11) =131a(12) =241a(13) =243a(14) =343a(15) =441a(16) =443a(17) =729a(18) =815a(19) =1331a(20) =1499a(21) =1521a(22) =2187a(23) =2401a(24) =2757a(25) =5041a(26) =5071a(27) =6561a(28) =9261a(29) =9327