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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 8 |
| 3 | 12 |
| 4 | 176 |
| 5 | 840 |
| 6 | 7416 |
| 7 | 58800 |
| 8 | 529728 |
| 9 | 5152896 |
| 10 | 54070560 |
| 11 | 612342720 |
| 12 | 7472424384 |
| 13 | 97979207040 |
| 14 | 1375839795456 |
| 15 | 20619488373120 |
| 16 | 328716465177600 |
| 17 | 5556948993792000 |
| 18 | 99324048442208256 |
| 19 | 1871986425192990720 |
| 20 | 37110785352536724480 |
| 21 | 772059856808638218240 |
| 22 | 16820447458491885035520 |
[1,0,8,12,176,840,7416,58800,529728,5152896, 54070560,612342720,7472424384,97979207040, 1375839795456,20619488373120,328716465177600, 5556948993792000,99324048442208256, 1871986425192990720,37110785352536724480, 772059856808638218240,16820447458491885035520] |