Question 158859
For three divisors, pick a small prime integer and square it. The divisors will be that number, 1 and the squared value. For instance, pick 2. 2*2 = 4. So the factors are 1, 2, 4

For four divisors, Pick two small prime numbers and multiply them. The facotrs will be those two numbers, 1 and the product of the two numbers. For instance, pick 2 and 3. Then you get 1, 2, 3, 6