(a) How many distinct 6-tuples of positive integers (a1,...,a6) are there such that a1+...+a6 = 14?
(b) How many distinct 6-tuples of nonnegative integers (a1,...,a6) are there such that a1+...+a6 = 14?
I'm thinking the only difference between (a) and (b) is that 0 is not allowed in (a)