Closest prime to 3^n (in case of a tie, choose the smaller prime).

Terms

a(0) =3a(1) =7a(2) =29a(3) =79a(4) =241a(5) =727a(6) =2179a(7) =6563a(8) =19681a(9) =59051a(10) =177131a(11) =531457a(12) =1594331a(13) =4782971a(14) =14348909a(15) =43046747a(16) =129140153a(17) =387420479a(18) =1162261453a(19) =3486784393a(20) =10460353199a(21) =31381059607a(22) =94143178807a(23) =282429536483a(24) =847288609457