Numbers k such that 3*R_k + 50 is prime, where R_k = 11...1 is the repunit (A002275) of length k.

A256800

Numbers k such that 3*R_k + 50 is prime, where R_k = 11...1 is the repunit (A002275) of length k.

Terms

    a(0) =1a(1) =2a(2) =3a(3) =6a(4) =7a(5) =13a(6) =22a(7) =28a(8) =32a(9) =126a(10) =172a(11) =186a(12) =267a(13) =650a(14) =693a(15) =1083a(16) =3783a(17) =12294a(18) =18134a(19) =53859a(20) =66650a(21) =72097a(22) =98890a(23) =125706a(24) =200001

External references