BdMO National Junior 2019/4

Discussion on Bangladesh Mathematical Olympiad (BdMO) National
samiul_samin
Posts:1007
Joined:Sat Dec 09, 2017 1:32 pm
BdMO National Junior 2019/4

Unread post by samiul_samin » Mon Mar 04, 2019 8:52 am

Find all positive integer $n$ such that $2019+n!$ is a perfect square.

Dustan
Posts:71
Joined:Mon Aug 17, 2020 10:02 pm

Re: BdMO National Junior 2019/4

Unread post by Dustan » Sun Sep 20, 2020 10:07 pm

n<4 there is no solution.
n>3
$2019+n!\congruent 3(mod 4)$
contradiction!

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