Numbers n such that 9*10^n + 5*R_n + 2 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
A103102
Numbers n such that 9*10^n + 5*R_n + 2 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
Terms
- a(0) =0a(1) =1a(2) =7a(3) =67a(4) =127a(5) =2107a(6) =10003a(7) =13741a(8) =41523
External references
- oeis: A103102