Largest prime factor of the n-th Jacobsthal number, A001045(n).

Terms

a(0) =3a(1) =5a(2) =11a(3) =7a(4) =43a(5) =17a(6) =19a(7) =31a(8) =683a(9) =13a(10) =2731a(11) =127a(12) =331a(13) =257a(14) =43691a(15) =73a(16) =174763a(17) =41a(18) =5419a(19) =683a(20) =2796203a(21) =241a(22) =4051a(23) =8191a(24) =87211a(25) =127a(26) =3033169a(27) =331a(28) =715827883a(29) =65537