(x+2y)^2(x-2y)^2-2(x+2y)(x-2y)
=(x+2y)^2(x-2y)^2-2(x+2y)(x-2y)+1-1
=[(x+2y)(x-2y)-1]^2+1
=(2006×2010-1)^2+1
=16257499779482