Largest prime factor of 2^n + 1.

Terms

a(0) =2a(1) =3a(2) =5a(3) =3a(4) =17a(5) =11a(6) =13a(7) =43a(8) =257a(9) =19a(10) =41a(11) =683a(12) =241a(13) =2731a(14) =113a(15) =331a(16) =65537a(17) =43691a(18) =109a(19) =174763a(20) =61681a(21) =5419a(22) =2113a(23) =2796203a(24) =673a(25) =4051a(26) =1613a(27) =87211a(28) =15790321a(29) =3033169