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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 6 |
| 5 | 720 |
| 6 | 2160 |
| 7 | 2419200 |
| 8 | 65318400 |
| 9 | 754427520000 |
| 10 | 32953394073600000 |
| 11 | 311409573995520000 |
| 12 | 37269497815783833600000 |
| 13 | 7890485108998805913600000000 |
| 14 | 1096106738916569123487744000000 |
| 15 | 4067286739206415827555188736000000000 |
| 16 | 7924734685010508814047938347008000000000000 |
[1,1,2,6,720,2160,2419200,65318400,754427520000, 32953394073600000,311409573995520000, 37269497815783833600000, 7890485108998805913600000000, 1096106738916569123487744000000, 4067286739206415827555188736000000000, 7924734685010508814047938347008000000000000] |