Numbers k such that 8*R_k + 3*10^k - 5 is prime, where R_k = 11...11 is the repunit (A002275) of length k.
A259127
Numbers k such that 8*R_k + 3*10^k - 5 is prime, where R_k = 11...11 is the repunit (A002275) of length k.
Terms
- a(0) =2a(1) =12a(2) =30a(3) =60a(4) =116a(5) =290a(6) =632a(7) =1064a(8) =1494a(9) =5432a(10) =7362
External references
- oeis: A259127