Numbers k such that (3^k + 1)/(3 - (-1)^k) is a prime.

Terms

a(0) =2a(1) =3a(2) =4a(3) =5a(4) =7a(5) =13a(6) =16a(7) =23a(8) =32a(9) =43a(10) =64a(11) =281a(12) =359a(13) =487a(14) =577a(15) =1579a(16) =1663a(17) =1741a(18) =3191a(19) =9209a(20) =11257a(21) =12743a(22) =13093a(23) =17027a(24) =26633a(25) =104243a(26) =134227a(27) =152287a(28) =700897a(29) =1205459