Numbers k such that 6*R_k + 7*10^k + 1 is prime, where R_k = 11...11 is the repunit (A002275) of length k.
A259133
Numbers k such that 6*R_k + 7*10^k + 1 is prime, where R_k = 11...11 is the repunit (A002275) of length k.
Terms
- a(0) =4a(1) =6a(2) =54a(3) =96a(4) =454a(5) =574a(6) =3384a(7) =11440a(8) =12624a(9) =19446a(10) =35460a(11) =81214a(12) =95326
External references
- oeis: A259133