n | a(n) |
---|---|
0 | 1 |
1 | 3 |
2 | 3 |
3 | 90 |
4 | 18 |
5 | 945 |
6 | 1890 |
7 | 12600 |
8 | 22680 |
9 | 53460 |
10 | 1247400 |
11 | 10216206000 |
12 | 157172400 |
13 | 1021620600 |
14 | 6129723600 |
15 | 534386160000 |
16 | 81729648000 |
17 | 2494674910728000 |
18 | 127932046704000 |
19 | 2744142401800800000 |
[1,3,3,90,18,945,1890,12600,22680,53460,1247400, 10216206000,157172400,1021620600,6129723600, 534386160000,81729648000,2494674910728000, 127932046704000,2744142401800800000] |