化简（3+1）（3的平方+1）（3的四次方+1）（3的八次方+1）

(3+1)(3^2+1)(3^4+1)(3^8+1)
=(1/2)*(3-1)*(3+1)(3^2+1)(3^4+1)(3^8+1)
=(1/2)*(3^2-1)(3^2+1)(3^4+1)(3^8+1)
=(1/2)*(3^4-1)(3^4+1)(3^8+1)
=(1/2)*(3^8-1)(3^8+1)
=(1/2)*(3^16-1)
=(3^16-1)/2