Fermat primes Memes

The mathematical pattern seemed so elegant. 2 1 +1=3, 2 2 +1=5, 2 4 +1=17... all prime numbers. Even 2 8 +1=257 and 2 16 +1=65537 are prime. So naturally, one might conclude that all numbers of the form 2 2 n +1 are prime. Except they're not. This is the Fermat prime conjecture trap. Fermat numbers F 5 and beyond are actually composite. F 5 = 2 32 +1 = 4,294,967,297 = 641 × 6,700,417. Mathematics: where induction from a few examples will make you look like that third panel. Number theory doesn't care about your feelings or your pattern-seeking brain.