No.24

Mathematical induction:
Step1. Prove n=1 is true
             Left hand side equal to the first number in the sequence
             Right hand side equal to the number when you plug n=1in the other side of the equation
             If left is equal to right, then the statement is true
Step2. Assume n=1is true. Prove n+1is true
             Left hand side is the sequence when you remove n by n+1
             Right hand side is the sequence when you also plug n+1
             If they are equal, the statement is true. Hence,