Deformation Failure Characteristics of Coal Body and Mining Induced Stress Evolution Law

Table 1

The void distribution of Sierpinski gasket.

𝑘	0	1	2	3	4	⋯	𝑘	⋯
𝐿𝑘	𝐿𝑐	2^−1𝐿𝑐	2^−2𝐿𝑐	2^−3𝐿𝑐	2^−4𝐿𝑐	⋯	2^−𝑘𝐿𝑐	⋯
𝑁	0	1	4	13	40	⋯	(3^𝑘−1)/2	⋯