Largest prime factor of 12^n - 1.

Terms

a(0) =11a(1) =13a(2) =157a(3) =29a(4) =22621a(5) =157a(6) =4943a(7) =233a(8) =80749a(9) =22621a(10) =266981089a(11) =20593a(12) =20369233a(13) =13063a(14) =22621a(15) =260753a(16) =74876782031a(17) =80749a(19) =85403261a(21) =57154490053a(22) =321218438243a(23) =2227777a(25) =20369233