Numbers k such that 3*10^k + 5*R_k + 4 is prime, where R_k = 11...1 is the repunit (A002275) of length k.

A102973

Numbers k such that 3*10^k + 5*R_k + 4 is prime, where R_k = 11...1 is the repunit (A002275) of length k.

Terms

    a(0) =0a(1) =2a(2) =3a(3) =5a(4) =8a(5) =14a(6) =77a(7) =195a(8) =218a(9) =957a(10) =1052a(11) =1163a(12) =1485a(13) =1731a(14) =1970a(15) =3237a(16) =17354a(17) =85964

External references