A250210 Irregular triangle read by rows in which row n lists the prime factors of the duodecimal repunit ((12^n-1)/11). (Written in base 10).

13, 157, 5, 13, 29, 22621, 7, 13, 19, 157, 659, 4943, 5, 13, 29, 89, 233, 37, 157, 80749, 13, 19141, 22621, 11, 23, 266981089, 5, 7, 13, 19, 29, 157, 20593, 477517, 20369233, 13, 211, 659, 4943, 13063, 61, 157, 661, 9781, 22621, 5, 13, 17, 29, 89, 97, 233, 260753

Offset: 2

Author

Eric Chen, Dec 29 2014

Keywords

• nonn
• tabf

Examples

			Triangle begins:
[13]
[157]
[5, 13, 29]
[22621]
[7, 13, 19, 157]
[659, 4943]
[5, 13, 29, 89, 233]
[37, 157, 80749]
[13, 19141, 22621]
...
		

Crossrefs

Cf. A102380, A004064, A250288.

Programs

PARI

tabf(nn) = for (n=1, nn, print(factor((12^n-1)/11)[,1]~);); \\ Michel Marcus, Dec 29 2014