What is f(x)=4x^5+16x^4-16x^3-x-6, D(x)=x^2-4? I am to use long division

I am stuck I got 4x^3+16x^2 but I am wrong can anyone explain how to properly approach this problem.

4x^5 + 16x^4 - 16x^3 - x - 6 Ix^2 - 4
......................................…
......................................… + 16x^2 + 64
-4x^5 + 16x^3
--------------------
16x^4 + 16x^3
-16x^4 + 64x^2
-----------------------
16x^3 + 64x^2 - 16x^3 = 64x^2
64x^2 - x
-64x^2 + 256
------------------
- x + 256 - 6 = - x + 250

Answer: 4x^3 + 16x^2 + 64 + (- x + 250)/(x^2 - 4)

(4 x^5 + 16 x^4 - 16 x^3 - x - 6)/(x^2 - 4)

4 x^3+16 x^2+62/(x-2)-63/(x+2)+64