Perfect powers pp(n) with perfect power index n.

Terms

a(0) =1a(1) =9a(2) =32a(3) =36a(4) =128a(5) =324a(6) =361a(7) =529a(8) =729a(9) =1444a(10) =2401a(11) =3969a(12) =6400a(13) =9261a(14) =10000a(15) =10609a(16) =13689a(17) =19321a(18) =26569a(19) =32761a(20) =35721a(21) =42025a(22) =47089a(23) =61009a(24) =77841a(25) =87025a(26) =97336a(27) =120409a(28) =147456a(29) =177241