Numbers k such that 90*R_k + 1 is prime, where R_k = 11...1 is the repunit (A002275) of length k.
A056696
Numbers k such that 90*R_k + 1 is prime, where R_k = 11...1 is the repunit (A002275) of length k.
Terms
- a(0) =2a(1) =4a(2) =6a(3) =32a(4) =44a(5) =104a(6) =196a(7) =198a(8) =280a(9) =300a(10) =316a(11) =1106a(12) =1656a(13) =3394a(14) =35924a(15) =37596a(16) =64304a(17) =80138a(18) =221630
External references
- oeis: A056696