13.9 Given several sets with identical contents, each set consists of 4 objects with integer gram weights. Now, we want to use these objects as weights to measure every integer gram weight from 1 gram to 1985 grams (including 1985 grams). To minimize the total weight of the objects used as weights, how many different ways are there to select the weights of the 4 objects?
［Solution］Obviously, the total weight of the objects used as weights cannot be less than 1985 grams, and
$$
1985=5 \times 397 .
$$

Thus, the minimum total weight of 4 objects in each set is 5. The only selection of 4 objects with integer gram weights is $\{1,1,1,2\}$.
Therefore, there is only one way to select the weights of 4 objects, and a total of 397 sets are selected.