Primes of the form 2^r*5^s + 1.

Terms

a(0) =2a(1) =3a(2) =5a(3) =11a(4) =17a(5) =41a(6) =101a(7) =251a(8) =257a(9) =401a(10) =641a(11) =1601a(12) =4001a(13) =16001a(14) =25601a(15) =40961a(16) =62501a(17) =65537a(18) =160001a(19) =163841a(20) =16384001a(21) =26214401a(22) =40960001a(23) =62500001a(24) =104857601a(25) =167772161a(26) =256000001a(27) =409600001a(28) =655360001a(29) =2441406251