Numbers k such that 5*10^k + R_k is prime, where R_k = 11...1 is the repunit (A002275) of length k.
A056713
Numbers k such that 5*10^k + R_k is prime, where R_k = 11...1 is the repunit (A002275) of length k.
Terms
- a(0) =0a(1) =5a(2) =12a(3) =15a(4) =84a(5) =144a(6) =150a(7) =1235a(8) =1727a(9) =1812a(10) =8687a(11) =12390a(12) =28608a(13) =42959a(14) =51111a(15) =96798a(16) =99143
External references
- oeis: A056713