Primes in A068947.

Terms

a(0) =2a(1) =3a(2) =7a(3) =13a(4) =17a(5) =43a(6) =83a(7) =167a(8) =313a(9) =1667a(10) =6833a(11) =8167a(12) =191833a(13) =298327a(14) =3143167a(15) =197222917a(16) =994927133