English

Binary-ternary collisions and the last significant digit of $n!$ in base 12

Number Theory 2024-12-13 v1

Abstract

The third-named author recently proved [Israel J. of Math. 258 (2023), 475--502] that there are infinitely many \textit{collisions} of the base-2 and base-3 sum-of-digits functions. In other words, the equation s2(n)=s3(n) s_2(n)=s_3(n) admits infinitely many solutions in natural numbers. We refine this result and prove that every integer aa in {1,2,,11}\{1, 2, \ldots, 11\} appears as the last nonzero digit of n!n! in base 1212 infinitely often.

Keywords

Cite

@article{arxiv.2412.09124,
  title  = {Binary-ternary collisions and the last significant digit of $n!$ in base 12},
  author = {Jean-Marc Deshouillers and Pascal Jelinek and Lukas Spiegelhofer},
  journal= {arXiv preprint arXiv:2412.09124},
  year   = {2024}
}

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11 pages