Largest prime factor of 9^n - 1.

Terms

a(0) =2a(1) =5a(2) =13a(3) =41a(4) =61a(5) =73a(6) =1093a(7) =193a(8) =757a(9) =1181a(10) =3851a(11) =6481a(12) =797161a(13) =16493a(14) =4561a(15) =21523361a(16) =34511a(17) =530713a(18) =363889a(19) =42521761a(20) =368089a(21) =570461a(22) =23535794707a(23) =6481a(24) =22996651a(25) =4795973261a(26) =19927a(27) =647753a(28) =20381027a(29) =47763361