Numbers n such that 3^n has the form 2p-+1 where p is prime.

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =7a(5) =13a(6) =16a(7) =32a(8) =64a(9) =71a(10) =103a(11) =541a(12) =1091a(13) =1367a(14) =1627a(15) =4177a(16) =9011a(17) =9551a(18) =36913a(19) =43063a(20) =49681a(21) =57917a(22) =483611a(23) =877843a(24) =2215303a(25) =2704981a(26) =3598867