n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 4 |
3 | 30 |
4 | 312 |
5 | 3720 |
6 | 64080 |
7 | 1305360 |
8 | 33949440 |
9 | 1019692800 |
10 | 36360576000 |
11 | 1487539468800 |
12 | 69633899596800 |
13 | 3649476307276800 |
14 | 213929162589542400 |
15 | 13848506938506240000 |
16 | 986705192227442688000 |
17 | 76724136092268048384000 |
18 | 6491471142159880740864000 |
[1,1,4,30,312,3720,64080,1305360,33949440, 1019692800,36360576000,1487539468800, 69633899596800,3649476307276800, 213929162589542400,13848506938506240000, 986705192227442688000,76724136092268048384000, 6491471142159880740864000] |