n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 1 |
3 | 1 |
4 | 2 |
5 | 6 |
6 | 18 |
7 | 54 |
8 | 216 |
9 | 1080 |
10 | 5400 |
11 | 27000 |
12 | 162000 |
13 | 1134000 |
14 | 7938000 |
15 | 55566000 |
16 | 444528000 |
17 | 4000752000 |
18 | 36006768000 |
19 | 324060912000 |
20 | 3240609120000 |
21 | 35646700320000 |
22 | 392113703520000 |
23 | 4313250738720000 |
[1,1,1,1,2,6,18,54,216,1080,5400,27000,162000, 1134000,7938000,55566000,444528000,4000752000, 36006768000,324060912000,3240609120000, 35646700320000,392113703520000,4313250738720000] |