Work Step by Step
In order to calculate the first $4$ terms of the sequence we will have to plug $ n=1,2,3,4$ into the given equation. So, we get $ a_1=-1,a_2=5, a_3=15; a_4=29; a_5=47$ Thus, we have the sum $=-1+5+15+29+47=95$
You can help us out by revising, improving and updating this answer.Update this answer
After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.