Let n be a natural number, and try to explain that the square difference between N + 5 and n-3 must be a multiple of 16?

Let n be a natural number, and try to explain that the square difference between N + 5 and n-3 must be a multiple of 16?

Their square difference is (n + 5 + n-3) (n + 5-N + 3) = 16N + 16, so it's a multiple of 16