Numbers n such that 6*10^n + 5*R_n - 2 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

A103039

Numbers n such that 6*10^n + 5*R_n - 2 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

Terms

    a(0) =2a(1) =3a(2) =9a(3) =11a(4) =12a(5) =15a(6) =36a(7) =38a(8) =41a(9) =77a(10) =90a(11) =96a(12) =132a(13) =374a(14) =399a(15) =617a(16) =1332a(17) =1395a(18) =1811a(19) =2804a(20) =4953a(21) =5310a(22) =16676a(23) =29336

External references