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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | -1 |
| 3 | 5 |
| 4 | -24 |
| 5 | 154 |
| 6 | -1170 |
| 7 | 10394 |
| 8 | -105392 |
| 9 | 1201524 |
| 10 | -15210180 |
| 11 | 211691380 |
| 12 | -3212711040 |
| 13 | 52801793160 |
| 14 | -934299180360 |
| 15 | 17708685967400 |
| 16 | -357960437635200 |
| 17 | 7686847410694800 |
| 18 | -174756587308650000 |
| 19 | 4193327411934706000 |
[0,1,-1,5,-24,154,-1170,10394,-105392,1201524, -15210180,211691380,-3212711040,52801793160, -934299180360,17708685967400,-357960437635200, 7686847410694800,-174756587308650000, 4193327411934706000] |