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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 135 |
| 4 | 403200 |
| 5 | 2778300000 |
| 6 | 483930961920000 |
| 7 | 7180239749742259200000 |
| 8 | 5799315033741817236160512000000 |
| 9 | 6429886152366060611794081018183680000000 |
| 10 | 466736302504188801174703321606427057848320000000000 |
| 11 | 23001739511849592885668155296556060490333421994770432000000000 |
[1,1,4,135,403200,2778300000,483930961920000, 7180239749742259200000, 5799315033741817236160512000000, 6429886152366060611794081018183680000000, 46673630250418880117470332160642705784832000000000\ 0, 23001739511849592885668155296556060490333421994770\ 432000000000] |