Primes of the form 4^k + 4^m - 1, where k and m are positive integers.

Terms

a(0) =7a(1) =19a(2) =31a(3) =67a(4) =79a(5) =127a(6) =271a(7) =1039a(8) =1087a(9) =1279a(10) =4099a(11) =4111a(12) =4159a(13) =5119a(14) =8191a(15) =16447a(16) =20479a(17) =65539a(18) =65551a(19) =65599a(20) =81919a(21) =131071a(22) =262147a(23) =262399a(24) =263167a(25) =266239a(26) =524287a(27) =1049599a(28) =1114111a(29) =1310719