Numbers n such that 9*10^n + 3*R_n + 4 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
A103096
Numbers n such that 9*10^n + 3*R_n + 4 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
Terms
- a(0) =0a(1) =1a(2) =2a(3) =3a(4) =4a(5) =15a(6) =27a(7) =71a(8) =86a(9) =105a(10) =242a(11) =250a(12) =448a(13) =539a(14) =784a(15) =814a(16) =1025a(17) =1172a(18) =1353a(19) =3009a(20) =3175a(21) =3682a(22) =6993a(23) =7612a(24) =7780a(25) =9633a(26) =27109a(27) =27735a(28) =28767a(29) =61574
External references
- oeis: A103096