n | a(n) |
---|---|
0 | 1 |
1 | 0 |
2 | 0 |
3 | 6 |
4 | 12 |
5 | 40 |
6 | 1620 |
7 | 16128 |
8 | 154560 |
9 | 3378240 |
10 | 67828320 |
11 | 1247843520 |
12 | 28996704000 |
13 | 773215822080 |
14 | 20900234234880 |
15 | 609432997219200 |
16 | 19677823129036800 |
17 | 674330219708221440 |
18 | 24327437969162280960 |
19 | 936555233579552563200 |
20 | 38250260222888409292800 |
[1,0,0,6,12,40,1620,16128,154560,3378240,67828320, 1247843520,28996704000,773215822080, 20900234234880,609432997219200,19677823129036800, 674330219708221440,24327437969162280960, 936555233579552563200,38250260222888409292800] |