n | a(n) |
---|---|
0 | 1 |
1 | 2 |
2 | 6 |
3 | 20 |
4 | 80 |
5 | 368 |
6 | 1904 |
7 | 10880 |
8 | 67904 |
9 | 459008 |
10 | 3336704 |
11 | 25925120 |
12 | 214175744 |
13 | 1873092608 |
14 | 17276401664 |
15 | 167504076800 |
16 | 1702214549504 |
17 | 18084149854208 |
18 | 200388963958784 |
19 | 2311212530401280 |
20 | 27693720143396864 |
21 | 344157474490155008 |
22 | 4428851361694613504 |
23 | 58933575269230837760 |
[1,2,6,20,80,368,1904,10880,67904,459008,3336704, 25925120,214175744,1873092608,17276401664, 167504076800,1702214549504,18084149854208, 200388963958784,2311212530401280, 27693720143396864,344157474490155008, 4428851361694613504,58933575269230837760] |