A001271 Irregular table read by rows: row n lists prime factors of 10^n +1, with multiplicity.

2, 11, 101, 7, 11, 13, 73, 137, 11, 9091, 101, 9901, 11, 909091, 17, 5882353, 7, 11, 13, 19, 52579, 101, 3541, 27961, 11, 11, 23, 4093, 8779, 73, 137, 99990001, 11, 859, 1058313049, 29, 101, 281, 121499449, 7, 11, 13, 211, 241, 2161, 9091, 353, 449, 641, 1409, 69857

Offset: 0

Author

N. J. A. Sloane, revised Jul 13 2009

Keywords

• nonn
• tabf

Comments

Except for 2, all these primes are in A028416, and all the primes in A028416 appear here. - Davide Rotondo, Aug 12 2023

Examples

			Table begins:
    2;
   11;
  101,
    7,      11, 13;
   73,     137;
   11,    9091;
  101,    9901;
   11,  909091;
   17, 5882353;
  ...
		

References

• J. Brillhart et al., Factorizations of b^n +- 1. Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 2nd edition, 1985; and later supplements.

Links

• Ray Chandler, Rows n=0..310, flattened (from Kamada link)
• J. Brillhart et al., Factorizations of b^n +- 1, Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 3rd edition, 2002.
• Makoto Kamada, Factorizations of 100...001.
• S. S. Wagstaff, Jr., The Cunningham Project

Crossrefs

Cf. A028416, A057934, A062397.

Extensions

Term ordering corrected by Sean A. Irvine, Apr 11 2012

Minor edits to description by Ray Chandler, May 02 2017