Numbers k such that R_(k+2) + 3*10^k is prime, where R_k = 11...1 is the repunit (A002275) of length k.
A256927
Numbers k such that R_(k+2) + 3*10^k is prime, where R_k = 11...1 is the repunit (A002275) of length k.
Terms
- a(0) =9a(1) =26a(2) =1268a(3) =14391
External references
- oeis: A256927