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

A103036

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

Terms

    a(0) =1a(1) =2a(2) =5a(3) =10a(4) =40a(5) =47a(6) =58a(7) =73a(8) =92a(9) =113a(10) =124a(11) =130a(12) =887a(13) =1234a(14) =1538a(15) =2063a(16) =2591a(17) =2786a(18) =3145a(19) =21688a(20) =32381a(21) =39170a(22) =47791a(23) =83878

External references