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| n | a(n) |
|---|---|
| 0 | 2 |
| 1 | 240 |
| 2 | 9676800 |
| 3 | 386266890240000 |
| 4 | 33674087438261157888000000 |
| 5 | 11977449554394932435557703221248000000000 |
| 6 | 29139961073721833036780987632259240162985246720000000000000 |
[2,240,9676800,386266890240000, 33674087438261157888000000, 11977449554394932435557703221248000000000, 29139961073721833036780987632259240162985246720000\ 000000000] |