Legal generalized repunit prime numbers.

Terms

a(0) =5a(1) =7a(2) =13a(3) =31a(4) =43a(5) =73a(6) =157a(7) =211a(8) =241a(9) =1093a(10) =2801a(11) =19531a(12) =22621a(13) =30941a(14) =55987a(15) =88741a(16) =245411a(17) =292561a(18) =346201a(19) =797161a(20) =5229043a(21) =8108731a(22) =12207031a(23) =25646167a(24) =305175781a(25) =321272407a(26) =917087137a(27) =16148168401