Smallest primitive factor of 10^n - 1. Also smallest prime p such that 1/p has repeating decimal expansion of period n.
A007138
Smallest primitive factor of 10^n - 1. Also smallest prime p such that 1/p has repeating decimal expansion of period n.
Terms
- a(0) =3a(1) =11a(2) =37a(3) =101a(4) =41a(5) =7a(6) =239a(7) =73a(8) =333667a(9) =9091a(10) =21649a(11) =9901a(12) =53a(13) =909091a(14) =31a(15) =17a(16) =2071723a(17) =19a(19) =3541a(20) =43a(21) =23a(23) =99990001a(24) =21401a(25) =859a(26) =757a(27) =29a(28) =3191a(29) =211a(30) =2791a(31) =353
External references
- oeis: A007138