(m - n + 1)*(m + n + 1)
1*(m + 1 + n)*(m + 1 - n)
(1*(m + (1 + n)))*(m + (1 - n))
(1.0 + m + n)*(1.0 + m - n)
2 2 1 + m - n + 2*m
1 + m^2 - n^2 + 2*m