Practical numbers among the binomial coefficients
Number Theory
2020-12-15 v1
Abstract
A "practical number" is a positive integer such that every positive integer less than can be written as a sum of distinct divisors of . We prove that most of the binomial coefficients are practical numbers. Precisely, letting denote the number of binomial coefficients , with , that are not practical numbers, we show that \begin{equation*} f(n) < n^{1 - (\log 2 - \delta)/\log \log n} \end{equation*} for all integers , but at most exceptions, for all and . Furthermore, we prove that the central binomial coefficient is a practical number for all positive integers but at most exceptions. We also pose some questions on this topic.
Keywords
Cite
@article{arxiv.1905.12023,
title = {Practical numbers among the binomial coefficients},
author = {Paolo Leonetti and Carlo Sanna},
journal= {arXiv preprint arXiv:1905.12023},
year = {2020}
}
Comments
10 pages, no figures