In researching for the formula to find the A's magic number we came across this site:
The Riot formula takes into account games in common, whereas the traditional magic number does not.
For example, the Mariners would have to win their next 20 games to win the AL West outright, the A's need 15 wins and the Angels 17. Which makes sense, since they are playing each other for the rest of the month. Wins mean more than losses at this point since they are all common games.
Frankly, we could care less. As long as Oakland keeps playing .999 baseball and shuts everyone out we would just be happy if we could start buying playoff tickets this week.