a(n) is the least prime p, such that next_prime(2*p) - 2*p = 2*n - 1.

Terms

a(0) =2a(1) =7a(2) =31a(3) =71a(4) =59a(5) =331a(6) =569a(7) =263a(8) =691a(9) =977a(10) =1091a(11) =2089a(12) =1487a(13) =2417a(14) =2797a(15) =10223a(16) =4987a(17) =6427a(18) =12743a(19) =9811a(20) =17041a(21) =29423a(22) =12739a(23) =20323a(24) =20147a(25) =17839a(26) =53017a(27) =53693a(28) =17033a(29) =67261