Numbers k such that 5*10^k + R_k + 6 is prime, where R_k = 11...1 is the repunit (A002275) of length k.
A103006
Numbers k such that 5*10^k + R_k + 6 is prime, where R_k = 11...1 is the repunit (A002275) of length k.
Terms
- a(0) =0a(1) =23a(2) =53a(3) =12809a(4) =15071
External references
- oeis: A103006