Answer:
1-5: Make it 5 units tall
6-10: Make it 4 units tall
11-15: Make it 2 units tall
16-20: Make it 0 units tall (Don't do anything to it)
21-25: Make it 4 units tall
Explanation:
1-5: 2, 3, 3, 3, 5 (5 numbers)
6-10: 6, 6, 8, 10 (4 numbers)
11-15: 11, 13 (2 numbers)
16-20: (0 numbers)
21-25: 22, 23, 24, 24 (4 numbers)