1:-2,4,-8,13,-32...2:-4,8,-16,32,-64.3:-4,2,-10,14,-34.找出各行规律,计算各组第8个数的和.

1:-2,4,-8,13,-32...2:-4,8,-16,32,-64.3:-4,2,-10,14,-34.找出各行规律,计算各组第8个数的和.
1:-2,4,-8,13,-32...2:-4,8,-16,32,-64.3:-4,2,-10,14,-34.找出各行规律,计算各组第8个数的和.

1:-2,4,-8,13,-32...2:-4,8,-16,32,-64.3:-4,2,-10,14,-34.找出各行规律,计算各组第8个数的和.
第一组;(-1)^n *2^n 第四个数比较特殊（减去前面个数）,所以依次类推第八个数为256-7=249
第二组;(-1)^n *2^(n+1）,所以第八个数为512
第三组：(-1)^n *2^n-2,所以第八个数为256-2=254
所以和为1015