Numbers k such that 2*10^k + R_k + 2 is prime, where R_k = 11...1 is the repunit (A002275) of length k.
A102948
Numbers k such that 2*10^k + R_k + 2 is prime, where R_k = 11...1 is the repunit (A002275) of length k.
Terms
- a(0) =1a(1) =3a(2) =7a(3) =13a(4) =24a(5) =30a(6) =48a(7) =52a(8) =163a(9) =175a(10) =219a(11) =228a(12) =261a(13) =754a(14) =951a(15) =1344a(16) =1573a(17) =3294a(18) =3523a(19) =14161a(20) =70794
External references
- oeis: A102948