Primes p such that 2^p - 1 has at most 2 prime factors.

Terms

a(0) =2a(1) =3a(2) =5a(3) =7a(4) =11a(5) =13a(6) =17a(7) =19a(8) =23a(9) =31a(10) =37a(11) =41a(12) =59a(13) =61a(14) =67a(15) =83a(16) =89a(17) =97a(18) =101a(19) =103a(20) =107a(21) =109a(22) =127a(23) =131a(24) =137a(25) =139a(26) =149a(27) =167a(28) =197a(29) =199