n | a(n) |
---|---|
0 | 0 |
1 | 0 |
2 | 0 |
3 | 2 |
4 | 8 |
5 | 40 |
6 | 200 |
7 | 1400 |
8 | 11200 |
9 | 103040 |
10 | 1030400 |
11 | 11334400 |
12 | 135766400 |
13 | 1764963200 |
14 | 24709484800 |
15 | 370687116800 |
16 | 5930993868800 |
17 | 100826895769600 |
18 | 1814871926067200 |
19 | 34482566595276800 |
20 | 689651331905536000 |
21 | 14482682605174784000 |
22 | 318619017313845248000 |
[0,0,0,2,8,40,200,1400,11200,103040,1030400, 11334400,135766400,1764963200,24709484800, 370687116800,5930993868800,100826895769600, 1814871926067200,34482566595276800, 689651331905536000,14482682605174784000, 318619017313845248000] |