English

Extending Babbage's (Non-)Primality Tests

Number Theory 2018-12-20 v1

Abstract

We recall Charles Babbage's 1819 criterion for primality, based on simultaneous congruences for binomial coefficients, and extend it to a least-prime-factor test. We also prove a partial converse of his non-primality test, based on a single congruence. Two problems are posed. Along the way we encounter Bachet, Bernoulli, Bezout, Euler, Fermat, Kummer, Lagrange, Lucas, Vandermonde, Waring, Wilson, Wolstenholme, and several contemporary mathematicians.

Cite

@article{arxiv.1812.07650,
  title  = {Extending Babbage's (Non-)Primality Tests},
  author = {Jonathan Sondow},
  journal= {arXiv preprint arXiv:1812.07650},
  year   = {2018}
}

Comments

10 pages, 1 figure

R2 v1 2026-06-23T06:47:01.224Z