Numbers n such that 6*10^n + 8*R_n - 5 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
A103045
Numbers n such that 6*10^n + 8*R_n - 5 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
Terms
- a(0) =2a(1) =3a(2) =8a(3) =50a(4) =56a(5) =72a(6) =108a(7) =132a(8) =182a(9) =1100a(10) =1368a(11) =1605a(12) =5132a(13) =22682
External references
- oeis: A103045