Research notes on every problem, and a library of the papers behind them. Built from the open erdos repository.
Updated
Claim. Every counted by is a product of two integers at most , so , the number of distinct entries of the multiplication table. Ford's theorem on the multiplication table (Corollary 3 of the paper, with ) gives
so . The paper
itself does not mention the problem. The one-line comparison was first posted
in the site's thread on 23 November 2025 by Wouter van Doorn, and the site's
commentary credited it to him until its edit of 2 May 2026. Chojecki's post
announcing the 2026 manuscript and the curator's post of 2 May 2026 both
attribute the upper bound to that comment. The claim value is proved, since
the result is a proved inequality, the upper half of the estimate that the
full claim records as answered.
Covers. The upper bound only. It settles the exponent of from above and leaves the lower bound, which the 2026 claim supplies.
Acceptance. Refereed: Kevin Ford, The distribution of integers with a divisor in a given interval, Annals of Mathematics (2) 168 (2008), no. 2, 367--433, DOI 10.4007/annals.2008.168.367 (issue dated September 2008, by its Crossref record); the library card is ford_2008_distribution_integers_divisor_given_interval. Reviewed: the site's curator, Thomas Bloom, rests the upper bound on this theorem in the commentary (last edited 2 May 2026). Nothing is independently reviewed by this project.
Date. The page is named by the arXiv posting of 18 January 2004, the result's first public appearance.