So I was watching a video on Leonhard Euler about how he amazingly solved so many difficult problems and one of the many problems that he solved was this:
Find four whole numbers, the sum of any two of which add up to a perfect square.
The numbers he found were: $$18530,~~~ 38114,~~~ 45986,~~~ 65570$$
I've searched everywhere on the net but I can't find how he solved this. Does anyone here know how he did it?