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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 12 |
| 4 | 864 |
| 5 | 14929920 |
| 6 | 37150418534400000 |
| 7 | 10063619980174622195712000000000000000 |
| 8 | 664903611914043473202543232567979684173499596800000000000000000000000000000000000 |
[1,2,12,864,14929920,37150418534400000, 10063619980174622195712000000000000000, 66490361191404347320254323256797968417349959680000\ 0000000000000000000000000000000] |