English

On the sum of digits of the factorial

Number Theory 2014-10-30 v1

Abstract

Let b > 1 be an integer and denote by s_b(m) the sum of the digits of the positive integer m when is written in base b. We prove that s_b(n!) > C_b log n log log log n for each integer n > e, where C_b is a positive constant depending only on b. This improves of a factor log log log n a previous lower bound for s_b(n!) given by Luca. We prove also the same inequality but with n! replaced by the least common multiple of 1,2,...,n.

Keywords

Cite

@article{arxiv.1409.4912,
  title  = {On the sum of digits of the factorial},
  author = {Carlo Sanna},
  journal= {arXiv preprint arXiv:1409.4912},
  year   = {2014}
}

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4 pages