n | a(n) |
---|---|
0 | 1 |
1 | 0 |
2 | 2 |
3 | 12 |
4 | 36 |
5 | 240 |
6 | 2280 |
7 | 15120 |
8 | 122640 |
9 | 1330560 |
10 | 13335840 |
11 | 136382400 |
12 | 1657212480 |
13 | 20860519680 |
14 | 262278656640 |
15 | 3585207225600 |
16 | 52249374777600 |
17 | 772773281280000 |
18 | 11907924610982400 |
19 | 193962388523904000 |
20 | 3253343368231756800 |
21 | 56051640629816832000 |
[1,0,2,12,36,240,2280,15120,122640,1330560, 13335840,136382400,1657212480,20860519680, 262278656640,3585207225600,52249374777600, 772773281280000,11907924610982400, 193962388523904000,3253343368231756800, 56051640629816832000] |