Second smallest distinct prime factor of repunit(n) = (10^n-1)/9 (A002275), zero if repunit is prime.
A176973
Second smallest distinct prime factor of repunit(n) = (10^n-1)/9 (A002275), zero if repunit is prime.
Terms
- a(0) =0a(1) =37a(2) =101a(3) =271a(4) =7a(5) =4649a(6) =73a(7) =37a(8) =41a(9) =513239a(10) =7a(11) =79a(12) =239a(13) =31a(14) =17a(15) =5363222357a(16) =7a(17) =0a(18) =41a(19) =37a(20) =23a(21) =0a(22) =7a(23) =271a(24) =53a(25) =37a(26) =29a(27) =16763a(28) =7a(29) =6943319
External references
- oeis: A176973