Primes of the form 2*k^3-1.

Terms

a(0) =53a(1) =127a(2) =431a(3) =1999a(4) =8191a(5) =18521a(6) =27647a(7) =31249a(8) =59581a(9) =78607a(10) =159013a(11) =194671a(12) =314927a(13) =332749a(14) =390223a(15) =453961a(16) =524287a(17) =657017a(18) =1062881a(19) =1457999a(20) =1507141a(21) =1608713a(22) =1940597a(23) =2519423a(24) =3455999a(25) =4000751a(26) =4393999a(27) =5371237a(28) =5606441