Smallest odd prime factor of 3^n - 1.

Terms

a(0) =13a(1) =5a(2) =11a(3) =7a(4) =1093a(5) =5a(6) =13a(7) =11a(8) =23a(9) =5a(10) =797161a(11) =547a(12) =11a(13) =5a(14) =1871a(15) =7a(16) =1597a(17) =5a(18) =13a(19) =23a(20) =47a(21) =5a(22) =11a(23) =398581a(24) =13a(25) =5a(26) =59a(27) =7a(28) =683a(29) =5