We show that if p ≠ 5 is a prime, then the numbers cover all the nonzero residue classes modulo p.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-cm96-2-4,
author = {Florian Luca and Pantelimon St\u anic\u a},
title = {Products of factorials modulo p},
journal = {Colloquium Mathematicae},
volume = {96},
year = {2003},
pages = {191-205},
zbl = {1042.11002},
language = {en},
url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-cm96-2-4}
}
Florian Luca; Pantelimon Stănică. Products of factorials modulo p. Colloquium Mathematicae, Tome 96 (2003) pp. 191-205. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-cm96-2-4/