Primes of form R_n + 2 {= (10^n + 17)/9}, R_n being the n-th repunit, i.e., primes consisting of a string of 1's followed by a terminal 3.
A105431
Primes of form R_n + 2 {= (10^n + 17)/9}, R_n being the n-th repunit, i.e., primes consisting of a string of 1's followed by a terminal 3.
Terms
- a(0) =3a(1) =13a(2) =113a(3) =1113a(4) =111113a(5) =1111111113a(6) =111111111113
External references
- oeis: A105431