Do you think we can find a formula that will work for adding all the integers from 1 to n?
Think about it! Look over the last three problems we just did -- see anything?
Let's write it out the same way:
How many pairs of n + 1 are there? Half of n!
Find the sum
(You know it will be 5050 + 101 = 5151.)
Does the formula work?
How would you write this series in sigma notation?