Numbers k such that 4^k + 9 is prime.

Terms

a(0) =1a(1) =3a(2) =5a(3) =9a(4) =15a(5) =33a(6) =41a(7) =335a(8) =443a(9) =671a(10) =1197a(11) =1355a(12) =2247a(13) =2639a(14) =117293a(15) =191099