39940

1,14,6,17 - 17 is higher than 15
2,13,7,16 - 16 is higher than 15
3,12,8,15,1,17 - 17 is higher than 15
4,11,9,14,2,16 - 16 is higher than 15
5,10,10 - 10 is repeated twice
6,9,11,12,4,14,7 - here is your solution
7,8,12,11,5,13,8 - 8 is repeated twice
8,7,13,10,6,12,9 - here is another solution
9,6,14,9 - 9 is repeated twice
10,5,15,8,8 - 8 is repeated twice
11,4,16 - 16 is higher than 15
13,2,18 - 18 is higher than 15
14,1,19 - 19 is higher than 15
15,0 - 0 is not counted

There are only 2 sequences that provide correct solutions to the problem.

There is also a pattern of +2 and -2 in each of the numbers of the solution.