This is a math problem I came across the other day:

$365$ can be written as a sum of two and also three consecutive perfect squares:

$365=14^2+13^2=12^2+11^2+10^2$

What is the next number with this property? Give the last 4 digits of the number.
The perfect squares cannot be zero.

I would like to know what would be a good way (esp. performance-wise) to check all first, lets say, 1000000, natural numbers if they can be represented in the way above, using *Mathematica*?