n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 2 |
3 | 5 |
4 | 20 |
5 | 100 |
6 | 610 |
7 | 4270 |
8 | 34160 |
9 | 307160 |
10 | 3071600 |
11 | 33787600 |
12 | 405466600 |
13 | 5271065800 |
14 | 73794921200 |
15 | 1106922416600 |
16 | 17710758665600 |
17 | 301082897315200 |
18 | 5419492342264000 |
19 | 102970354503016000 |
20 | 2059407090060320000 |
21 | 43247548855054544000 |
22 | 951446074811199968000 |
[1,1,2,5,20,100,610,4270,34160,307160,3071600, 33787600,405466600,5271065800,73794921200, 1106922416600,17710758665600,301082897315200, 5419492342264000,102970354503016000, 2059407090060320000,43247548855054544000, 951446074811199968000] |