Numbers k such that 6*R_k + 10^k - 5 is prime, where R_k = 11...11 is the repunit (A002275) of length k.
A259118
Numbers k such that 6*R_k + 10^k - 5 is prime, where R_k = 11...11 is the repunit (A002275) of length k.
Terms
- a(0) =1a(1) =4a(2) =12a(3) =16a(4) =18a(5) =36a(6) =52a(7) =72a(8) =100a(9) =6232a(10) =24028a(11) =40222a(12) =66394
External references
- oeis: A259118