n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 2 |
3 | 7 |
4 | 36 |
5 | 240 |
6 | 1930 |
7 | 17990 |
8 | 189840 |
9 | 2233000 |
10 | 28949200 |
11 | 410009600 |
12 | 6297999400 |
13 | 104275571400 |
14 | 1851050401200 |
15 | 35065930299400 |
16 | 705993054166400 |
17 | 15051593241484800 |
18 | 338705933426660800 |
19 | 8021585392026606400 |
20 | 199416162740963168000 |
21 | 5191567315003621552000 |
[1,1,2,7,36,240,1930,17990,189840,2233000, 28949200,410009600,6297999400,104275571400, 1851050401200,35065930299400,705993054166400, 15051593241484800,338705933426660800, 8021585392026606400,199416162740963168000, 5191567315003621552000] |