找规律, 2,2,4,8,14,26,48,88___?1,-2,-3,4,5,-6,-7,8,9``````,2005,-2006,-2007,2008的和是
问题描述：
找规律, 2,2,4,8,14,26,48,88___?1,-2,-3,4,5,-6,-7,8,9``````,2005,-2006,-2007,2008的和是
答
从第4个数开始,每个数等于前三个数的和.2+2+4=8 2+4+8=14 8+14+26=48 14+26+48=88 所以:26+48+88=1621,-2,-3,4,5,-6,-7,8,9``````,2005,-2006,-2007,2008=1+2×（2009-1）/2-2009=0还有什么不明白的地方再问我....