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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 8 |
| 3 | 456 |
| 4 | 182400 |
| 5 | 510902400 |
| 6 | 10017774259200 |
| 7 | 1375009641495014400 |
| 8 | 1321109263548409835520000 |
| 9 | 8885253784030448738183147520000 |
| 10 | 418310711031156574478261944188764160000 |
| 11 | 137856159231156714984163673320892478249861120000 |
[1,1,8,456,182400,510902400,10017774259200, 1375009641495014400,1321109263548409835520000, 8885253784030448738183147520000, 418310711031156574478261944188764160000, 137856159231156714984163673320892478249861120000] |