前两个数:2^50=2*2^492^50-2^49=2*(2^49)-2^49=(2-1)2^49=2^49同理到第三个:2^49-2^48=2^48...到倒数第二个:2^2-2=2最后一个:2-1=1
设原式=a 则2a=2^50+2^49+省略号+2+1 2a-a=2^ 50-1=a
t=2^49+2^48+2^47+2^46…+2+12t=2^50+2^49+2^48+2^47+2^46…+2相减t=2^50-1