Thank you for using the site. I'll be happy to help you.
I'm not sure that I clearly understand the expression as it is typed above. Are there limits on the summation?
Is this meant to be the sum of "k-squared", from k = 1 to k = 4 perhaps?
If the expression looks like the one in the attached image, then the answer is 30.
If the expression is something different, then please let me know what needs to change.
Were you able to look at the image that I sent? Is there anything that needs to be changed with the expression?