I have removed the stem, I believe that it is an American Standard 2h 2k. However, I cannot get the seat out. It doesn't seem to have the square indention for the seat wrench. The last help I received in removing the stem was perfect. Thanks!

Some seats require a square tool to remove, some require a hex or Allen wrench to remove. Note that one end of this type of seat wrench is square, the other is hex.