Numbers n such that 6*10^n + 4*R_n + 5 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
A103037
Numbers n such that 6*10^n + 4*R_n + 5 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
Terms
- a(0) =0a(1) =3a(2) =105a(3) =627a(4) =687a(5) =699a(6) =5715a(7) =11391a(8) =11673
External references
- oeis: A103037