The number of sets satisfying that the sum of elements is equal to the product of elements If a set element belongs to a positive integer, find the number of all sets that satisfy that the sum of elements is equal to the product of elements

The number of sets satisfying that the sum of elements is equal to the product of elements If a set element belongs to a positive integer, find the number of all sets that satisfy that the sum of elements is equal to the product of elements

When there is no 1 in the element, the smallest element is 2. Let a belong to a
2a=a+a>a+2
Therefore, the set must contain 1
If the set contains four or more elements, it is denoted as n
You can see that there are at most three elements
There can't be two elements
Therefore, only 1 + 2 + 3 = 1 * 2 * 3 is consistent
The number of all sets whose sum of elements is equal to the product of elements is 1