n | a(n) |
---|---|
0 | 0 |
1 | 0 |
2 | 1 |
3 | 9 |
4 | 72 |
5 | 600 |
6 | 5400 |
7 | 52920 |
8 | 564480 |
9 | 6531840 |
10 | 81648000 |
11 | 1097712000 |
12 | 15807052800 |
13 | 242853811200 |
14 | 3966612249600 |
15 | 68652904320000 |
16 | 1255367393280000 |
17 | 24186745110528000 |
18 | 489781588488192000 |
19 | 10400656084955136000 |
20 | 231125690776780800000 |
21 | 5364548928029491200000 |
[0,0,1,9,72,600,5400,52920,564480,6531840, 81648000,1097712000,15807052800,242853811200, 3966612249600,68652904320000,1255367393280000, 24186745110528000,489781588488192000, 10400656084955136000,231125690776780800000, 5364548928029491200000] |