n | a(n) |
---|---|
0 | 0 |
1 | 1 |
2 | 2 |
3 | 8 |
4 | 40 |
5 | 224 |
6 | 1344 |
7 | 8448 |
8 | 54912 |
9 | 366080 |
10 | 2489344 |
11 | 17199104 |
12 | 120393728 |
13 | 852017152 |
14 | 6085836800 |
15 | 43818024960 |
16 | 317680680960 |
17 | 2317200261120 |
18 | 16992801914880 |
19 | 125210119372800 |
20 | 926554883358720 |
21 | 6882979133521920 |
[0,1,2,8,40,224,1344,8448,54912,366080,2489344, 17199104,120393728,852017152,6085836800, 43818024960,317680680960,2317200261120, 16992801914880,125210119372800,926554883358720, 6882979133521920] |