Numbers k such that 7*10^k + R_k + 8 is prime, where R_k = 11...1 is the repunit (A002275) of length k.
A103051
Numbers k such that 7*10^k + R_k + 8 is prime, where R_k = 11...1 is the repunit (A002275) of length k.
Terms
- a(0) =1a(1) =2a(2) =4a(3) =17a(4) =25a(5) =32a(6) =50a(7) =74a(8) =173a(9) =1724a(10) =2084a(11) =11398
External references
- oeis: A103051