Numbers k such that R_k + 8 is prime, where R_k = 11...1 is the repunit (A002275) of length k.
A097685
Numbers k such that R_k + 8 is prime, where R_k = 11...1 is the repunit (A002275) of length k.
Terms
- a(0) =2a(1) =5a(2) =6a(3) =8a(4) =17a(5) =50a(6) =684a(7) =720a(8) =1452a(9) =1679a(10) =3146a(11) =72821a(12) =111902a(13) =146063a(14) =180689a(15) =330906
External references
- oeis: A097685