Numbers k such that 2*3^k - 1 is prime.

Terms

a(0) =1a(1) =2a(2) =3a(3) =7a(4) =8a(5) =12a(6) =20a(7) =23a(8) =27a(9) =35a(10) =56a(11) =62a(12) =68a(13) =131a(14) =222a(15) =384a(16) =387a(17) =579a(18) =644a(19) =1772a(20) =3751a(21) =5270a(22) =6335a(23) =8544a(24) =9204a(25) =12312a(26) =18806a(27) =21114a(28) =49340a(29) =75551