n | a(n) |
---|---|
1 | 1 |
2 | 0 |
3 | 1 |
4 | 4 |
5 | 18 |
6 | 96 |
7 | 600 |
8 | 4320 |
9 | 35280 |
10 | 322560 |
11 | 3265920 |
12 | 36288000 |
13 | 439084800 |
14 | 5748019200 |
15 | 80951270400 |
16 | 1220496076800 |
17 | 19615115520000 |
18 | 334764638208000 |
19 | 6046686277632000 |
20 | 115242726703104000 |
21 | 2311256907767808000 |
22 | 48658040163532800000 |
23 | 1072909785605898240000 |
[1,0,1,4,18,96,600,4320,35280,322560,3265920, 36288000,439084800,5748019200,80951270400, 1220496076800,19615115520000,334764638208000, 6046686277632000,115242726703104000, 2311256907767808000,48658040163532800000, 1072909785605898240000] |