Numbers n such that 4*10^n + 3*R_n + 6 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

A102990

Numbers n such that 4*10^n + 3*R_n + 6 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

Terms

    a(0) =2a(1) =3a(2) =6a(3) =11a(4) =15a(5) =26a(6) =28a(7) =51a(8) =150a(9) =182a(10) =228a(11) =407a(12) =638a(13) =3581a(14) =4125a(15) =4983a(16) =5666a(17) =15890a(18) =27743a(19) =43362a(20) =55367a(21) =60744a(22) =73701

External references