原式可化为2^0+2^1+2^2+2^3+.+2^(5n-1) =(2^0+2^1+2^2+2^3+2^4)+(2^5+2^6+2^7+2^8+2^9)+……+{2^(5n-5)+2^(5n-4)+2^(5n-3)+2^(5n-2)+2^(5n-1)} =2^0*(2^0+2^1+2^2+2^3+2^4)+2...