Numbers k such that 5*2^k + 1 is prime.

Terms

a(0) =1a(1) =3a(2) =7a(3) =13a(4) =15a(5) =25a(6) =39a(7) =55a(8) =75a(9) =85a(10) =127a(11) =1947a(12) =3313a(13) =4687a(14) =5947a(15) =13165a(16) =23473a(17) =26607a(18) =125413a(19) =209787a(20) =240937a(21) =819739a(22) =1282755a(23) =1320487a(24) =1777515