(x-a+1)^4*y^2

1

(x-a-1)*(x-a+1)^3*(-2*a-2)^2

1

(x-a-1)^2*(x-a+1)^2*(-2*a-2)*(-2*a+2)

-2

-(x-a-1)^2*(x-a+1)^2*y^2

2

(x-a-1)^3*(x-a+1)*(-2*a+2)^2

1

(x-a-1)^4*y^2

1