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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | -4 |
| 4 | -36 |
| 5 | 14 |
| 6 | 3100 |
| 7 | 22112 |
| 8 | -374640 |
| 9 | -9520320 |
| 10 | 9674808 |
| 11 | 4085208192 |
| 12 | 55207595520 |
| 13 | -1640647901088 |
| 14 | -69445046214336 |
| 15 | 103240707929088 |
| 16 | 71686341699216384 |
| 17 | 1439635203885275136 |
| 18 | -60449514895261440000 |
| 19 | -3608840044036879934976 |
[1,1,1,-4,-36,14,3100,22112,-374640,-9520320, 9674808,4085208192,55207595520,-1640647901088, -69445046214336,103240707929088,71686341699216384, 1439635203885275136,-60449514895261440000, -3608840044036879934976] |