Though incorrect, this is meant to be an example of proof by induction. Proof by induction is (to simplify a little) where you prove that any number N+1 will h

Though incorrect, this is meant to be an example of proof by induction. Proof by induction is (to simplify a little) where you prove that any number N+1 will have a given property as long as N has that property. You can use this same rule twice to prove that N+2 has this property, and so on. Finally, you prove that any arbitrary number (say, 1) has the property in another way, and you've proven that property for all N greater than or equal to 1. The error in the proof is explained in the linked page, but basically the problem is that the proof that N implies N+1 doesn't actually work for all N, and particularly it doesn't let us go from 1 to 2.