Composite numbers k such that tau(k^(k-1)) is a prime.

Terms

a(0) =4a(1) =9a(2) =16a(3) =27a(4) =49a(5) =64a(6) =121a(7) =125a(8) =169a(9) =289a(10) =1681a(11) =1849a(12) =2401a(13) =3481a(14) =4913a(15) =5329a(16) =11881a(17) =12769a(18) =16129a(19) =18769a(20) =24649a(21) =29791a(22) =32041a(23) =32761a(24) =38809a(25) =39601a(26) =44521a(27) =63001a(28) =69169a(29) =76729