Primes of the form 90*R_k + 1, where R_k is the repunit (A002275) of length k.

A093177

Primes of the form 90*R_k + 1, where R_k is the repunit (A002275) of length k.

Terms

    a(0) =991a(1) =99991a(2) =9999991

External references