Just to clarify, your series is defined as;
You have a sequence of real numbers, , and you want to compute the sum
Do you have any more information on your numbers ?
Find ∑(x_i+i)^2 for i=5 to 168
x_i represents the 'i'th value in the list of x values.
I'm not really sure how to compute this. I'm worked with convergence tests and stuff for series, not familiar with solving this. More specifically, I don't understand what x_i represents in a way that I can plug it in and get a number for it.
Well, I guess what you could do is;
Here you can at least get with the formula given at Square pyramidal number - Wikipedia, the free encyclopedia, use it for n=168 and the substract n=5. For the other two, nothing comes to my mind as of yet without any precisions on the sequence .