Irregular triangle read by rows in which row n lists prime factors (with multiplicity) of the repunit (10^n - 1)/9 (A002275(n)).
A102380
Irregular triangle read by rows in which row n lists prime factors (with multiplicity) of the repunit (10^n - 1)/9 (A002275(n)).
Terms
- a(0) =1a(1) =11a(2) =3a(3) =37a(4) =11a(5) =101a(6) =41a(7) =271a(8) =3a(9) =7a(10) =11a(11) =13a(12) =37a(13) =239a(14) =4649a(15) =11a(16) =73a(17) =101a(18) =137a(19) =3a(20) =3a(21) =37a(22) =333667a(23) =11a(24) =41a(25) =271a(26) =9091a(27) =21649a(28) =513239a(29) =3
External references
- oeis: A102380