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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 48 |
| 4 | 1104 |
| 5 | 54408 |
| 6 | 5624336 |
| 7 | 1223018480 |
| 8 | 559805180336 |
| 9 | 539124008193384 |
| 10 | 1092375543732930912 |
| 11 | 4656812532055124194440 |
| 12 | 41767144321757757477117792 |
[1,4,48,1104,54408,5624336,1223018480, 559805180336,539124008193384,1092375543732930912, 4656812532055124194440,41767144321757757477117792] |