Smallest prime of the form (k^2 * 2^n + 1).

Terms

a(0) =3a(1) =5a(2) =73a(3) =17a(4) =1153a(5) =257a(6) =1153a(7) =257a(8) =18433a(9) =25601a(10) =18433a(11) =65537a(12) =1179649a(13) =65537a(14) =1179649a(15) =65537a(16) =1179649a(17) =26214401a(18) =117964801a(19) =26214401a(20) =169869313a(21) =104857601a(22) =2717908993a(23) =10485760001a(24) =2717908993a(25) =11341398017a(26) =10871635969a(27) =52613349377