function collatz(n)
	io.write(n)
	while n > 1 do
		if (n % 2) == 0 then
			n = n // 2
		else
			n = 3 * n + 1
		end
		io.write(' ' .. n)
	end
	io.write('\n')
end

assert(#arg ~= 0, 'expected initial number')
collatz(tonumber(arg[1]))