n | a(n) |
---|---|
0 | 0 |
1 | 0 |
2 | 2 |
3 | 16 |
4 | 116 |
5 | 888 |
6 | 7416 |
7 | 67968 |
8 | 682272 |
9 | 7467840 |
10 | 88678080 |
11 | 1136712960 |
12 | 15655438080 |
13 | 230672171520 |
14 | 3621985113600 |
15 | 60392753971200 |
16 | 1065907048550400 |
17 | 19855856150323200 |
18 | 389354639411404800 |
19 | 8017578241634304000 |
20 | 172991656889856000000 |
21 | 3903132531903897600000 |
[0,0,2,16,116,888,7416,67968,682272,7467840, 88678080,1136712960,15655438080,230672171520, 3621985113600,60392753971200,1065907048550400, 19855856150323200,389354639411404800, 8017578241634304000,172991656889856000000, 3903132531903897600000] |