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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 6 |
| 2 | 720 |
| 3 | 3628800 |
| 4 | 1316818944000 |
| 5 | 52563198423859200000 |
| 6 | 327312129899898454671360000000 |
| 7 | 428017682605583614976547335700480000000000 |
| 8 | 152240508705590071980086429193304853792686080000000000000 |
[1,6,720,3628800,1316818944000, 52563198423859200000, 327312129899898454671360000000, 428017682605583614976547335700480000000000, 15224050870559007198008642919330485379268608000000\ 0000000] |