n = \pm 1^2 \pm 2^2 \pm 3^2 \pm ... \pm k^2
Source: 8th QEDMO problem 2 (15. 1. 2011) https://artofproblemsolving.com/community/c1512515_qedmo_200507
May 15, 2021
number theorySum of Squares
Problem Statement
Let be an integer. Show that a natural number can be found for which, the following applies with a suitable choice of signs: