n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 2 |
3 | 4 |
4 | 16 |
5 | 80 |
6 | 520 |
7 | 3640 |
8 | 29120 |
9 | 259840 |
10 | 2598400 |
11 | 28582400 |
12 | 343235200 |
13 | 4462057600 |
14 | 62468806400 |
15 | 936987251200 |
16 | 14991796019200 |
17 | 254860532326400 |
18 | 4587501779660800 |
19 | 87162533813555200 |
20 | 1743250676271104000 |
21 | 36608259566534656000 |
22 | 805381710463762432000 |
[1,1,2,4,16,80,520,3640,29120,259840,2598400, 28582400,343235200,4462057600,62468806400, 936987251200,14991796019200,254860532326400, 4587501779660800,87162533813555200, 1743250676271104000,36608259566534656000, 805381710463762432000] |