Suppose a number N can be written as P times Q times R times..., where all of P, Q, R... can each be written as the sum of two perfect nonzero squares.
Show that in this case N itself can also be written as the sum of two perfect squares.
(In reply to
re: Not so fast! by Jer)
Ah, thanks Jer. It only took me 10.5 years to get it.