Numbers k such that 70*R_k + 1 is prime, where R_k = 11...1 is the repunit (A002275) of length k.
A056688
Numbers k such that 70*R_k + 1 is prime, where R_k = 11...1 is the repunit (A002275) of length k.
Terms
- a(0) =1a(1) =12a(2) =19a(3) =22a(4) =30a(5) =99a(6) =240a(7) =274a(8) =924a(9) =1066a(10) =1368a(11) =2064a(12) =7162a(13) =37962a(14) =91855a(15) =111705a(16) =260197a(17) =271756a(18) =314563a(19) =348723
External references
- oeis: A056688