Smallest prime factor of 2^n-3.

Terms

a(0) =1a(1) =5a(2) =13a(3) =29a(4) =61a(5) =5a(6) =11a(7) =509a(8) =1021a(9) =5a(10) =4093a(11) =19a(12) =16381a(13) =5a(14) =13a(15) =53a(16) =11a(17) =5a(18) =1048573a(19) =773a(20) =4194301a(21) =5a(22) =16777213a(23) =479a(24) =37a(25) =5a(26) =11a(27) =536870909a(28) =23a(29) =5