Numbers n such that 6*10^n + R_n + 2 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
A103027
Numbers n such that 6*10^n + R_n + 2 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
Terms
- a(0) =2a(1) =3a(2) =5a(3) =11a(4) =12a(5) =23a(6) =75a(7) =101a(8) =122a(9) =173a(10) =647a(11) =2015a(12) =2684a(13) =11700a(14) =19625
External references
- oeis: A103027