My post on ∑ k ^ -n from December could perhaps use some clarifying.
If C = 0 or C = 1, the sum is still simple.
In December’s post, I used k as a constant and n is more conventionally called i. Here I am using C as the constant and using k for the i that is usually used.
C can also have the values of positive or negative integers or decimals except for 0 and 1.
To clarify or perhaps use a slightly less opaque layer of mud: