Numbers k such that 7*R_k + 10 is prime, where R_k = 11...1 is the repunit (A002275) of length k.
A256906
Numbers k such that 7*R_k + 10 is prime, where R_k = 11...1 is the repunit (A002275) of length k.
Terms
- a(0) =1a(1) =3a(2) =6a(3) =15a(4) =21a(5) =24a(6) =31a(7) =291a(8) =408a(9) =457a(10) =643a(11) =2671a(12) =2676a(13) =10893a(14) =21151a(15) =26445a(16) =77304a(17) =96312
External references
- oeis: A256906