Numbers n such that 5*10^n + 6*R_n + 3 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

A103018

Numbers n such that 5*10^n + 6*R_n + 3 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

Terms

    a(0) =1a(1) =2a(2) =3a(3) =10a(4) =25a(5) =29a(6) =34a(7) =73a(8) =76a(9) =77a(10) =651a(11) =884a(12) =938a(13) =1252a(14) =1893a(15) =3342a(16) =4034a(17) =6168a(18) =6216a(19) =6231a(20) =6812a(21) =11046a(22) =15448a(23) =16628a(24) =16918a(25) =18734a(26) =45935a(27) =130393a(28) =139289a(29) =158819

External references