LOL not necessarily. If you look deeper in the pattern you will notice, that sum of the first two terms is 2+3=5 (or 2+3 = 5+0). The next couple produces a sum of 3+5=8, and we can rewrite it as 3+5=7+1; following the logic you will get the answer: 5+7 = x -2. Solve for x => x = 10! =))))) But I would have gone with a prime too