# Sum of Consecutive Integers

Let n be an integer greater than 1, show that 2^{n} is the sum of two consecutive **odd** integers. Furthermore, show that 3^{n} is the sum of three consecutive integers.

- 4 August, 2012 -
- Article, Math Problems -
- Tags : 104 problems, number theory, titu
- 0 Comments

## Table Of Content

These can all be easily proven via construction.

### 1. There exists two consecutive odd integers whose sum is

If there exists two odd consecutive odd integers satisfying the above property, then it must be the case that such that

(1)

Since , then and are consecutive integers whose sum satisfies the above properties.

### 2. There exists three consecutive integers whose sum is

Suppose there exists three consecutive integers whose sum is , then because is necessarily odd, it must be the case that must also be odd as well. Since the sum of an even number and an odd number is still odd, must be even.

(2)

Hence, the sum of is

In fact, you can easily show that

and that

etc. Hence, using similar constructions, one can show that given an expression of the form : if is odd, then there exists consecutive integers whose sum is ; on the other hand, if is even, then there exists consecutive odd integers whose sum is .