Question

如图所示,由一些点组成形和三角形的图形,每条“边”(包括两个顶点)有n(n>1)个点,每个图形总的

Answer 1

n = 2,S = 3 = 3 x 1

n = 3,S = 6 = 3 x 2

n = 4,S = 9 = 3 x 3

n = n,S = 3 x (n-1)

n = 5,S = 3 x (5-1) = 12

n = 7,S = 3 x (7-1) = 18

n = 11,S = 3 x (11-1) = 30