Prime powers n such that both tau(n^2) and sigma(n^2) are composite numbers.

Terms

a(0) =16a(1) =81a(2) =128a(3) =625a(4) =1024a(5) =2187a(6) =2401a(7) =4096a(8) =8192a(9) =14641a(10) =28561a(11) =59049a(12) =65536a(13) =78125a(14) =83521a(15) =130321a(16) =131072a(17) =279841a(18) =524288a(19) =531441a(20) =707281a(21) =823543a(22) =923521a(23) =1594323a(24) =1874161a(25) =2825761a(26) =3418801a(27) =4194304a(28) =4879681a(29) =7890481