Largest nonrepunit base-n absolute prime (conjectured).

Terms

a(0) =7a(1) =53a(2) =3121a(3) =211a(4) =1999a(5) =3803a(6) =6469a(7) =991a(8) =161047a(9) =19793a(10) =16477a(11) =24907a(12) =683437a(13) =3547a(14) =67853a(15) =80273a(16) =94109a(17) =72421