(1+3)(1+3^2)(1+3^4)(1+3^8)…(1+3^32)
=(1-3)(1+3)(1+3^2)(1+3^4)(1+3^8)…(1+3^32)/(1-3)
=(1-3²)(1+3^2)(1+3^4)(1+3^8)…(1+3^32)/(-2)
=(1-3^4)(1+3^4)(1+3^8)…(1+3^32)/(-2)
=(1-3^8)(1+3^8)…(1+3^32)/(-2)
=(1-3^16)(1+3^16)(1+3^32)/(-2)
=(1-3^32)(1+3^32)/(-2)
等于(1-3^64)/(-2)