Primes of the form 3^k + 3^m - 1, where k and m are positive integers.

Terms

a(0) =5a(1) =11a(2) =17a(3) =29a(4) =53a(5) =83a(6) =89a(7) =107a(8) =251a(9) =269a(10) =809a(11) =971a(12) =2213a(13) =2267a(14) =4373a(15) =6563a(16) =6569a(17) =6803a(18) =8747a(19) =13121a(20) =19709a(21) =19763a(22) =20411a(23) =59051a(24) =65609a(25) =177173a(26) =183707a(27) =531521a(28) =538001a(29) =590489