Discrete Mathematics and it's applications - Kenneth Rosen
<a href="http://www.bookdepository.com/Discrete-Mathematics-Its-Applications-Kenneth-Rosen/9780071315012" rel="nofollow">http://www.bookdepository.com/Discrete-Mathematics-Its-Appli...</a><p>Once you finish that, get to Concrete Mathematics by Donald Knuth et. al.