n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 1 |
3 | 2 |
4 | 4 |
5 | 12 |
6 | 48 |
7 | 240 |
8 | 1440 |
9 | 11520 |
10 | 115200 |
11 | 1382400 |
12 | 20736000 |
13 | 373248000 |
14 | 8211456000 |
15 | 221709312000 |
16 | 7094697984000 |
17 | 269598523392000 |
18 | 12401532076032000 |
19 | 669682732105728000 |
20 | 42859694854766592000 |
[1,1,1,2,4,12,48,240,1440,11520,115200,1382400, 20736000,373248000,8211456000,221709312000, 7094697984000,269598523392000,12401532076032000, 669682732105728000,42859694854766592000] |