Numbers k such that 6*10^k + R_k is prime, where R_k = 11...1 is the repunit (A002275) of length k.
A056717
Numbers k such that 6*10^k + R_k is prime, where R_k = 11...1 is the repunit (A002275) of length k.
Terms
- a(0) =1a(1) =5a(2) =7a(3) =25a(4) =31a(5) =112a(6) =199a(7) =533a(8) =616a(9) =718a(10) =787a(11) =1357a(12) =2779a(13) =3889a(14) =4192a(15) =7537a(16) =7945a(17) =23938a(18) =32632a(19) =49169a(20) =56453a(21) =61097a(22) =90211
External references
- oeis: A056717