should be pretty slow

matrix.lua

function matrixpower(m, n)
	local d = #m
	local temp = {}
	local mm = {}
	for i = 1, d do
		temp[i] = {}
		mm[i] = {}
		for j = 1, d do
			mm[i][j] = m[i][j]
		end
	end
	for k = 1, n - 1 do
		for i = 1, d do for j = 1, d do
			temp[i][j] = 0
			for ii = 1, d do
				temp[i][j] = temp[i][j] + mm[i][ii] * m[ii][j]
			end
		end end
		for i = 1, d do for j = 1, d do
			mm[i][j] = temp[i][j]
		end end
	end
	return mm
end

a=matrixpower({{1,2,3},{4,5,6} ,{7,8,9}}, 3)
for i=1,3 do for j=1,3 do print(a[i][j]) end end