Numbers k such that 10^k + 6*R_k + 1 is prime, where R_k = 11...1 is the repunit (A002275) of length k.
A102940
Numbers k such that 10^k + 6*R_k + 1 is prime, where R_k = 11...1 is the repunit (A002275) of length k.
Terms
- a(0) =0a(1) =1a(2) =2a(3) =3a(4) =5a(5) =9a(6) =11a(7) =14a(8) =32a(9) =54a(10) =55a(11) =60a(12) =153a(13) =200a(14) =461a(15) =569a(16) =840a(17) =847a(18) =1296a(19) =1356a(20) =2007a(21) =2627a(22) =2847a(23) =3110a(24) =6876a(25) =9161a(26) =17765a(27) =33555a(28) =59142a(29) =65773
External references
- oeis: A102940