Numbers k such that k*4^k-1 is prime.

Terms

a(0) =1a(1) =2a(2) =3a(3) =5a(4) =8a(5) =14a(6) =23a(7) =63a(8) =107a(9) =132a(10) =428a(11) =530a(12) =1137a(13) =1973a(14) =2000a(15) =7064a(16) =20747a(17) =79574a(18) =113570a(19) =293912a(20) =1993191