Summation Program
<p>I am trying to create a simple function that will take the summation numbers given an integer from 0. For example, If the user inputs the integer 3, the results would be 6, since 0 + 1 + 2 + 3 = 6.</p>

<p>What is the best/most efficient way to do this?</p>

<p>Eventually I want to create a loop that will do this for a list, where the user inputs the list [4, 5, 6] and the function would return [10, 15, 16].</p>

<p>Thanks in advance!</p>