Numbers k such that 4k + 1 is prime.

Terms

a(0) =1a(1) =3a(2) =4a(3) =7a(4) =9a(5) =10a(6) =13a(7) =15a(8) =18a(9) =22a(10) =24a(11) =25a(12) =27a(13) =28a(14) =34a(15) =37a(16) =39a(17) =43a(18) =45a(19) =48a(20) =49a(21) =57a(22) =58a(23) =60a(24) =64a(25) =67a(26) =69a(27) =70a(28) =73a(29) =78