Prime powers p^w (w >= 2) such that p^w-2 is prime.

Terms

a(0) =4a(1) =9a(2) =25a(3) =49a(4) =81a(5) =169a(6) =243a(7) =361a(8) =729a(9) =841a(10) =1369a(11) =1849a(12) =2209a(13) =2401a(14) =3721a(15) =5041a(16) =6859a(17) =7921a(18) =10609a(19) =11449a(20) =14641a(21) =16129a(22) =17161a(23) =19321a(24) =19683a(25) =28561a(26) =29791a(27) =29929a(28) =36481a(29) =44521