Odd prime factors of generalized Fermat numbers of the form 7^(2^m) + 1 with m >= 0.

Terms

a(0) =5a(1) =17a(2) =257a(3) =353a(4) =769a(5) =1201a(6) =12289a(7) =13313a(8) =35969a(9) =65537a(10) =114689a(11) =163841a(12) =169553a(13) =7699649a(14) =9379841a(15) =11886593a(16) =28667393a(17) =64749569a(18) =70254593a(19) =134818753a(20) =197231873a(21) =4643094529a(22) =19847446529a(23) =47072139617a(24) =206158430209a(25) =452850614273a(26) =531968664833a(27) =943558259713