n | a(n) |
---|---|
0 | 1 |
1 | 0 |
2 | 0 |
3 | 6 |
4 | 12 |
5 | 20 |
6 | 390 |
7 | 2562 |
8 | 11816 |
9 | 105912 |
10 | 1063530 |
11 | 8815070 |
12 | 81342492 |
13 | 895185876 |
14 | 9971185406 |
15 | 112642410090 |
16 | 1372455608400 |
17 | 17750397057392 |
18 | 236950003516626 |
19 | 3286258330135734 |
20 | 47688868443593540 |
21 | 719345273005797900 |
22 | 11222288509573985382 |
23 | 181168865439054099266 |
[1,0,0,6,12,20,390,2562,11816,105912,1063530, 8815070,81342492,895185876,9971185406, 112642410090,1372455608400,17750397057392, 236950003516626,3286258330135734, 47688868443593540,719345273005797900, 11222288509573985382,181168865439054099266] |