(5+1)(5的平方+1)(5的四次方+1)（5的八次方）……(5的64次方+1)

=(5-1)(5+1)(5^2+1)(5^4+1)……(5^64+1)/(5-1) =(5^2-1)(5^2+1)(5^4+1)……(5^64+1)/(5-1) =(5^4-1)(5^4+1)……(5^64+1)/(5-1) =(5^8-1)……(5^64+1)/(5-1) …… …… =(5^128-1)/4 =5^128/4-1/4