6-full numbers: if p divides n then so does p^6.

Terms

a(0) =1a(1) =64a(2) =128a(3) =256a(4) =512a(5) =729a(6) =1024a(7) =2048a(8) =2187a(9) =4096a(10) =6561a(11) =8192a(12) =15625a(13) =16384a(14) =19683a(15) =32768a(16) =46656a(17) =59049a(18) =65536a(19) =78125a(20) =93312a(21) =117649a(22) =131072a(23) =139968a(24) =177147a(25) =186624a(26) =262144a(27) =279936a(28) =373248a(29) =390625