Numbers k such that 10^k + 2*R_k + 1 is prime, where R_k = 11...1 is the repunit (A002275) of length k.
A102929
Numbers k such that 10^k + 2*R_k + 1 is prime, where R_k = 11...1 is the repunit (A002275) of length k.
Terms
- a(0) =0a(1) =1a(2) =3a(3) =9a(4) =48a(5) =58a(6) =153a(7) =261a(8) =876a(9) =1179a(10) =1596a(11) =17715a(12) =63718
External references
- oeis: A102929