以下是2009年高考数学湖南卷的第15题.将正△ABC分割成n2(n≥2,n∈N*)个全等的小正三角形(图1,图2分别给出了n=2,3的情形),在每个三角形的顶点各放置一个数,使位于△ABC的三边及平行于某边的任一直线上的数(当数的个数不少于3时)都分别依次成等差数列.若顶点A,B,C处的三个数互 The following is the Hunan University mathematics in 2009 college entrance examination questions 15. The positive △ ABC is divided into n2 (n ≥ 2, n∈N *) congruent small triangle (Figure 1, Figure 2 are given n = 2 , 3), a number is placed at each vertex of each triangle such that the number on either side of △ ABC and on any line parallel to one side (when the number of the numbers is not less than 3) Followed by a series of equal difference.If the vertices A, B, C at the three numbers of each other