Least prime p of the form c*3^n+1 with c not divisible by 3.

Terms

a(0) =2a(1) =7a(2) =19a(3) =109a(4) =163a(5) =487a(6) =1459a(7) =17497a(8) =52489a(9) =39367a(10) =472393a(11) =4960117a(12) =5314411a(13) =102036673a(14) =19131877a(15) =57395629a(16) =86093443a(17) =258280327a(18) =3874204891a(19) =23245229341a(20) =90656394427a(21) =585779779369a(22) =251048476873