Numbers k such that 5*10^k + R_k + 8 is prime, where R_k = 11...1 is the repunit (A002275) of length k.
A103007
Numbers k such that 5*10^k + R_k + 8 is prime, where R_k = 11...1 is the repunit (A002275) of length k.
Terms
- a(0) =0a(1) =1a(2) =3a(3) =7a(4) =15a(5) =22a(6) =189a(7) =445a(8) =543a(9) =633a(10) =757a(11) =8725a(12) =9003a(13) =37402
External references
- oeis: A103007