Prime factors of numbers of the form 4^(2^m) - 2^(2^m) + 1 with m >= 0.

Terms

a(0) =3a(1) =13a(2) =97a(3) =193a(4) =241a(5) =673a(6) =769a(7) =12289a(8) =786433a(9) =22253377a(10) =39714817a(11) =152371201a(12) =597688321a(13) =1107296257a(14) =3221225473a(15) =7348420609a(16) =11560943617a(17) =29796335617a(18) =74490839041a(19) =77309411329a(20) =206158430209a(21) =246423748609a(22) =448203325441