Smallest prime factor of 2^n + 1.

Terms

a(0) =3a(1) =5a(2) =3a(3) =17a(4) =3a(5) =5a(6) =3a(7) =257a(8) =3a(9) =5a(10) =3a(11) =17a(12) =3a(13) =5a(14) =3a(15) =65537a(16) =3a(17) =5a(18) =3a(19) =17a(20) =3a(21) =5a(22) =3a(23) =97a(24) =3a(25) =5a(26) =3a(27) =17a(28) =3a(29) =5