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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 8 |
| 3 | 180 |
| 4 | 8064 |
| 5 | 604800 |
| 6 | 68428800 |
| 7 | 10897286400 |
| 8 | 2324754432000 |
| 9 | 640237370572800 |
| 10 | 221172909834240000 |
| 11 | 93666727314800640000 |
| 12 | 47726800133326110720000 |
| 13 | 28806532937614688256000000 |
| 14 | 20325889640780924033433600000 |
| 15 | 16578303738261941164769280000000 |
[1,1,8,180,8064,604800,68428800,10897286400, 2324754432000,640237370572800,221172909834240000, 93666727314800640000,47726800133326110720000, 28806532937614688256000000, 20325889640780924033433600000, 16578303738261941164769280000000] |