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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 12 |
| 5 | -120 |
| 6 | 1020 |
| 7 | -8820 |
| 8 | 89628 |
| 9 | -1109808 |
| 10 | 15992160 |
| 11 | -253374000 |
| 12 | 4306032192 |
| 13 | -78317306496 |
| 14 | 1529483150832 |
| 15 | -32072509450800 |
| 16 | 719140990648848 |
| 17 | -17146103389588608 |
| 18 | 432647748528869376 |
[1,0,0,0,12,-120,1020,-8820,89628,-1109808, 15992160,-253374000,4306032192,-78317306496, 1529483150832,-32072509450800,719140990648848, -17146103389588608,432647748528869376] |