| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 0 |
| 3 | 12 |
| 4 | 96 |
| 5 | 3120 |
| 6 | 115200 |
| 7 | 5836320 |
| 8 | 382072320 |
| 9 | 31488549120 |
| 10 | 3191834419200 |
| 11 | 390445460697600 |
| 12 | 56729732529254400 |
| 13 | 9659308746908620800 |
| 14 | 1905270127543015833600 |
| 15 | 431026303509734220288000 |
| 16 | 110865322076320374571008000 |
| 17 | 32172949121885378686623744000 |
[1,0,0,12,96,3120,115200,5836320,382072320, 31488549120,3191834419200,390445460697600, 56729732529254400,9659308746908620800, 1905270127543015833600,431026303509734220288000, 110865322076320374571008000, 32172949121885378686623744000] |