Least prime factor of (4^(2n+1)+1)/5, a(0) = 1.

Terms

a(0) =1a(1) =13a(2) =5a(3) =29a(4) =13a(5) =397a(6) =53a(7) =5a(8) =137a(9) =229a(10) =13a(11) =277a(12) =5a(13) =13a(14) =107367629a(15) =5581a(16) =13a(17) =5a(18) =149a(19) =13a(20) =10169a(21) =173a(22) =5a(23) =3761a(24) =29a(25) =13a(26) =15358129a(27) =5a(28) =13a(29) =1181