Numbers k such that 80*R_k + 3 is prime, where R_k = 11...1 is the repunit (A002275) of length k.

A056694

Numbers k such that 80*R_k + 3 is prime, where R_k = 11...1 is the repunit (A002275) of length k.

Terms

    a(0) =0a(1) =1a(2) =2a(3) =4a(4) =7a(5) =8a(6) =14a(7) =50a(8) =70a(9) =76a(10) =223a(11) =295a(12) =314a(13) =2089a(14) =2905a(15) =3394a(16) =3881a(17) =5113a(18) =6055a(19) =7253a(20) =7994a(21) =18172a(22) =18970a(23) =35005a(24) =69673

External references