n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 2 |
3 | 6 |
4 | 12 |
5 | 20 |
6 | 60 |
7 | 252 |
8 | 672 |
9 | 1440 |
10 | 5400 |
11 | 27720 |
12 | 88704 |
13 | 224640 |
14 | 982800 |
15 | 5821200 |
16 | 21288960 |
17 | 61102080 |
18 | 300736800 |
19 | 1990850400 |
20 | 8089804800 |
21 | 25662873600 |
22 | 138940401600 |
23 | 1007370302400 |
24 | 4465572249600 |
25 | 15397724160000 |
26 | 90311261040000 |
27 | 707173952284800 |
28 | 3375972620697600 |
[1,1,2,6,12,20,60,252,672,1440,5400,27720,88704, 224640,982800,5821200,21288960,61102080,300736800, 1990850400,8089804800,25662873600,138940401600, 1007370302400,4465572249600,15397724160000, 90311261040000,707173952284800,3375972620697600] |