n | a(n) |
---|---|
0 | 1 |
1 | 0 |
2 | 0 |
3 | 0 |
4 | 8 |
5 | 20 |
6 | 80 |
7 | 420 |
8 | 11648 |
9 | 100800 |
10 | 912000 |
11 | 9055200 |
12 | 181547520 |
13 | 2790627840 |
14 | 41568334080 |
15 | 635617382400 |
16 | 13172198645760 |
17 | 273158953267200 |
18 | 5632405756723200 |
19 | 117530452124467200 |
20 | 2815021136030515200 |
21 | 71252240659839590400 |
22 | 1844362570865444044800 |
[1,0,0,0,8,20,80,420,11648,100800,912000,9055200, 181547520,2790627840,41568334080,635617382400, 13172198645760,273158953267200,5632405756723200, 117530452124467200,2815021136030515200, 71252240659839590400,1844362570865444044800] |