Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The Omega constant is a mathematical constant, a mathematical constant is a special number, usually a real number, that arises naturally in mathematics. Unlike physical constants, mathematical constants are defined independently of physical measurement. Some mathematical constants, such as e and , arise in many different contexts. Others, such as Graham''s number or Skewes'' number, only arise in a single specific context, but are notable because they are the earliest found, largest or smallest exemplar of a class of numbers. Many of the more interesting mathematical constants have a name, also when they can easily be specified by a short formula. What it means for a constant to arise "naturally", and what makes a constant "interesting", is ultimately a matter of taste, and some mathematical constants are notable more for historical reasons than for their intrinsic mathematical interest.