Odd Coin Weighing Algorithm

Consider the following scenario and then develop an algorithm to solve it. Suppose you have 9 coins and one of them is heavier than others. Other 8 coins weight equally. You are also given a balance. Develop an algorithm to determine the heavy coin using only two measurements using the balance. Now, suppose you have n coins and one of them is heavier. You can assume that n is a power of 3. Generalize the algorithm you have developed above for this case. What is the running time of your algorithm?

I understand how to solve the problem mathematically, but I can't seem to figure out how to write the algorithms in pseudo code.