Numbers k such that 20^k + 3 is prime.

Terms

a(0) =1a(1) =5a(2) =7a(3) =13a(4) =15a(5) =18a(6) =22a(7) =61a(8) =85a(9) =208a(10) =271a(11) =898a(12) =2142a(13) =2856a(14) =4392a(15) =17171a(16) =74886a(17) =78901a(18) =271951a(19) =326600