Numbers k such that 3*R_k + 40 is prime, where R_k = 11...1 is the repunit (A002275) of length k.

A256606

Numbers k such that 3*R_k + 40 is prime, where R_k = 11...1 is the repunit (A002275) of length k.

Terms

    a(0) =1a(1) =2a(2) =3a(3) =4a(4) =7a(5) =8a(6) =33a(7) =38a(8) =157a(9) =252a(10) =359a(11) =365a(12) =567a(13) =876a(14) =3108a(15) =5780a(16) =12987a(17) =14984a(18) =22287a(19) =31574a(20) =37473a(21) =40984a(22) =49806a(23) =51364a(24) =62451

External references