Numbers k such that 80*R_k + 9 is prime, where R_k = 11...1 is the repunit (A002275) of length k.
A056663
Numbers k such that 80*R_k + 9 is prime, where R_k = 11...1 is the repunit (A002275) of length k.
Terms
- a(0) =1a(1) =13a(2) =16a(3) =34a(4) =4174a(5) =4471a(6) =9811a(7) =12259a(8) =12340a(9) =13759a(10) =14575a(11) =53410a(12) =144682a(13) =148327
External references
- oeis: A056663