Numbers k such that floor(2^k / 5) is a prime.

Terms

a(0) =4a(1) =11a(2) =15a(3) =23a(4) =35a(5) =71a(6) =95a(7) =183a(8) =475a(9) =579a(10) =631a(11) =759a(12) =1519a(13) =1771a(14) =3031a(15) =6035a(16) =6951a(17) =11423a(18) =37451a(19) =51935a(20) =68051