Numbers n such that 3*10^n + 4*R_n + 3 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
A102969
Numbers n such that 3*10^n + 4*R_n + 3 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
Terms
- a(0) =1a(1) =2a(2) =758a(3) =1334a(4) =2177a(5) =4439a(6) =5198a(7) =6683a(8) =35990a(9) =47135
External references
- oeis: A102969