There are infinitely many possible rules. The following rule gives the next number as 13.
Un = (-25n3 + 195n2 - 380n + 228)/6 for n = 1, 2, 3, ...
The sequence decreases in a pattern: the first two numbers decrease by 2 (38 to 36), then by 6 (36 to 30), again by 2 (30 to 28), and finally by 6 (28 to 22). Following this pattern, the next decrease should be by 2, resulting in 22 - 2 = 20. Therefore, the next number in the sequence is 20.
20
20
20
The answer is: 12.
The next number in the sequence is 20. This is because the sequence is decreasing by 2, then decreasing by 6, then decreasing by 2, and then decreasing by 6. So, the next step would be to decrease by 2 again, resulting in the number 20.
18
20
20
12
20
20
20
The answer is: 12.
20? Just a guess
29, assuming it is an algebraically reclusive sequence.
58