Least prime p such that p+1 is divisible by 2^n and not by 2^(n+1).

Terms

a(0) =2a(1) =5a(2) =3a(3) =7a(4) =47a(5) =31a(6) =191a(7) =127a(8) =1279a(9) =3583a(10) =5119a(11) =6143a(12) =20479a(13) =8191a(14) =81919a(15) =294911a(16) =1114111a(17) =131071a(18) =786431a(19) =524287a(20) =17825791a(21) =14680063a(22) =138412031a(23) =109051903a(24) =654311423a(25) =1912602623a(26) =738197503a(27) =2818572287a(28) =7247757311a(29) =3758096383