Numbers n such that 6*10^n + 8*R_n + 1 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
A103047
Numbers n such that 6*10^n + 8*R_n + 1 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
Terms
- a(0) =5a(1) =57a(2) =501a(3) =515a(4) =627a(5) =641a(6) =725a(7) =53111a(8) =65331a(9) =109673
External references
- oeis: A103047