n | a(n) |
---|---|
0 | 0 |
1 | 0 |
2 | 1 |
3 | 3 |
4 | 18 |
5 | 90 |
6 | 660 |
7 | 4620 |
8 | 42000 |
9 | 378000 |
10 | 4142880 |
11 | 45571680 |
12 | 586776960 |
13 | 7628100480 |
14 | 113020427520 |
15 | 1695306412800 |
16 | 28432576972800 |
17 | 483353808537600 |
18 | 9056055981772800 |
19 | 172065063653683200 |
20 | 3562946373482496000 |
21 | 74821873843132416000 |
22 | 1697172166720622592000 |
[0,0,1,3,18,90,660,4620,42000,378000,4142880, 45571680,586776960,7628100480,113020427520, 1695306412800,28432576972800,483353808537600, 9056055981772800,172065063653683200, 3562946373482496000,74821873843132416000, 1697172166720622592000] |