Largest prime factor of 2^n-3.

Terms

a(0) =1a(1) =5a(2) =13a(3) =29a(4) =61a(5) =5a(6) =23a(7) =509a(8) =1021a(9) =409a(10) =4093a(11) =431a(12) =16381a(13) =6553a(14) =71a(15) =2473a(16) =23831a(17) =97a(18) =1048573a(19) =2713a(20) =4194301a(21) =1677721a(22) =16777213a(23) =70051a(24) =5197a(25) =31033a(26) =1877171a(27) =536870909a(28) =46684427a(29) =22605091