An alternating sum of the floor function of square roots

Fuente: arXiv
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Main Authors: Chamberland, Marc, Dilcher, Karl
Format: Preprint
Published: 2025
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author Chamberland, Marc
Dilcher, Karl
author_facet Chamberland, Marc
Dilcher, Karl
contents We show that the alternating sum of the floor function of $\sqrt{jn}$, with $j$ ranging from 1 to $n$, has an easy evaluation for all odd integers $n\geq 1$. This is in contrast to known non-alternating sums of the same type which hold only for a class of primes. The proof is elementary and was suggested by an AI model. To put this result in perspective, we also prove an asymptotic expression for the analogous sum without the floor function.
format Preprint
id arxiv_https___arxiv_org_abs_2510_26291
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle An alternating sum of the floor function of square roots
Chamberland, Marc
Dilcher, Karl
Number Theory
Primary 11A25, Secondary 11B83
We show that the alternating sum of the floor function of $\sqrt{jn}$, with $j$ ranging from 1 to $n$, has an easy evaluation for all odd integers $n\geq 1$. This is in contrast to known non-alternating sums of the same type which hold only for a class of primes. The proof is elementary and was suggested by an AI model. To put this result in perspective, we also prove an asymptotic expression for the analogous sum without the floor function.
title An alternating sum of the floor function of square roots
topic Number Theory
Primary 11A25, Secondary 11B83
url https://arxiv.org/abs/2510.26291