The problem is that if I let maple to do the explicit sum I've not a symbolic and compact answer
because I can't "recognize" the summation terms (this will be excessively time expensive, nearly that do the calculus by hand!!!).
On the other hand if I use the add command, maple don't expand the summation, and there is no simplifications!)
Obviously I've reversed the role of "add" and "sum"
About the use of add ad sum: if I create this array:
it work. But if I do the same declaration with sum (or Sum) at the place of the two "add", maple print
Error, bad index into Array
So, how can I do create an array which entries are unevalued sum, without bad index error?