Numbers k such that 61*2^k-1 is prime.

Terms

a(0) =3a(1) =5a(2) =9a(3) =13a(4) =17a(5) =19a(6) =25a(7) =39a(8) =63a(9) =67a(10) =75a(11) =119a(12) =147a(13) =225a(14) =419a(15) =715a(16) =895a(17) =1025a(18) =1103a(19) =1179a(20) =1345a(21) =1829a(22) =3855a(23) =4159a(24) =4493a(25) =6039a(26) =7799a(27) =9073a(28) =10543a(29) =12883