Numbers n such that 4*10^n + R_n + 8 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
A102983
Numbers n such that 4*10^n + R_n + 8 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
Terms
- a(0) =2a(1) =5a(2) =77a(3) =206a(4) =1871a(5) =3887a(6) =11582a(7) =20234a(8) =60290
External references
- oeis: A102983