Numbers k such that 7*10^k + 3*R_k + 6 is prime, where R_k = 11...1 is the repunit (A002275) of length k.
A103056
Numbers k such that 7*10^k + 3*R_k + 6 is prime, where R_k = 11...1 is the repunit (A002275) of length k.
Terms
- a(0) =0a(1) =1a(2) =2a(3) =5a(4) =7a(5) =85a(6) =345a(7) =1595a(8) =2105a(9) =6386a(10) =9119a(11) =9332a(12) =14707a(13) =72560
External references
- oeis: A103056