n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 2 |
3 | 12 |
4 | 52 |
5 | 280 |
6 | 2160 |
7 | 16870 |
8 | 150080 |
9 | 1557360 |
10 | 17491600 |
11 | 215908000 |
12 | 2923905600 |
13 | 42734091400 |
14 | 672515043200 |
15 | 11347480544400 |
16 | 204142655516800 |
17 | 3902009862150400 |
18 | 78976503077472000 |
19 | 1687212801048174400 |
20 | 37941749192547200000 |
[1,1,2,12,52,280,2160,16870,150080,1557360, 17491600,215908000,2923905600,42734091400, 672515043200,11347480544400,204142655516800, 3902009862150400,78976503077472000, 1687212801048174400,37941749192547200000] |