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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 12 |
| 5 | 60 |
| 6 | 240 |
| 7 | 1680 |
| 8 | 18480 |
| 9 | 45360 |
| 10 | 574560 |
| 11 | 6320160 |
| 12 | 19293120 |
| 13 | 250810560 |
| 14 | 3615131520 |
| 15 | 10637827200 |
| 16 | 173837664000 |
| 17 | 2955240288000 |
| 18 | 8874542476800 |
| 19 | 168616307059200 |
| 20 | 3378360124339200 |
| 21 | 10123012406707200 |
| 22 | 222987858828134400 |
| 23 | 5128720753047091200 |
[0,0,0,0,12,60,240,1680,18480,45360,574560, 6320160,19293120,250810560,3615131520,10637827200, 173837664000,2955240288000,8874542476800, 168616307059200,3378360124339200, 10123012406707200,222987858828134400, 5128720753047091200] |