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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | -2 |
| 3 | 24 |
| 4 | 382 |
| 5 | 3480 |
| 6 | 26398 |
| 7 | 183624 |
| 8 | 1217662 |
| 9 | 7844280 |
| 10 | 49595998 |
| 11 | 309603624 |
| 12 | 1915345342 |
| 13 | 11771312280 |
| 14 | 71987479198 |
| 15 | 438579414024 |
| 16 | 2664184199422 |
| 17 | 16146411375480 |
| 18 | 97676153291998 |
| 19 | 590010215086824 |
| 20 | 3559688013155902 |
| 21 | 21455704981601880 |
| 22 | 129219894496730398 |
| 23 | 777738831236334024 |
[1,0,-2,24,382,3480,26398,183624,1217662,7844280, 49595998,309603624,1915345342,11771312280, 71987479198,438579414024,2664184199422, 16146411375480,97676153291998,590010215086824, 3559688013155902,21455704981601880, 129219894496730398,777738831236334024] |