Numbers k such that 4^k + 19 is prime.

Terms

a(0) =1a(1) =3a(2) =15a(3) =81a(4) =327a(5) =357a(6) =685a(7) =831a(8) =861a(9) =1405a(10) =38571a(11) =78127a(12) =216487a(13) =546121a(14) =622615