cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A001270 Table of prime factors of 10^n - 1 (with multiplicity).

Original entry on oeis.org

3, 3, 3, 3, 11, 3, 3, 3, 37, 3, 3, 11, 101, 3, 3, 41, 271, 3, 3, 3, 7, 11, 13, 37, 3, 3, 239, 4649, 3, 3, 11, 73, 101, 137, 3, 3, 3, 3, 37, 333667, 3, 3, 11, 41, 271, 9091, 3, 3, 21649, 513239, 3, 3, 3, 7, 11, 13, 37, 101, 9901, 3, 3, 53, 79, 265371653
Offset: 1

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Keywords

Comments

The length of the n-th row is A057951(n).

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.

Crossrefs

Cf. A002283.

Programs

  • Mathematica
    Table[f = FactorInteger[10^n - 1]; Flatten[Table[Table[i[[1]], {i[[2]]}], {i, f}]], {n, 13}] (* T. D. Noe, Jun 27 2012 *)

Extensions

Erroneous b-file replaced by Ray Chandler, Apr 26 2017
b-file corrected and extended with rows 323..352 by Max Alekseyev, May 23 2023