Vì n và n + 1 là 2 STN liên tiếp nên đa thức có dạng:
\(\left(\right. �^{2 �} - 1 \left.\right) \left(\right. �^{2 � + 1} - 1 \left.\right)\)
\(= \left(\right. �^{2} - 1 \left.\right) � \left(\right. � \left.\right) \left(\right. � - 1 \left.\right) � \left(\right. � \left.\right)\)
\(= \left(\right. � - 1 \left.\right) \left(\right. � + 1 \left.\right) � \left(\right. � \left.\right) \left(\right. � - 1 \left.\right) � \left(\right. � \left.\right)\)
\(= \left(\right. � + 1 \left.\right) \left(\left(\right. � - 1 \left.\right)\right)^{2} � \left(\right. � \left.\right) � \left(\right. � \left.\right) \left(\right. � + 1 \left.\right) \left(\left(\right. � - 1 \left.\right)\right)^{2}\)
