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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 0 |
| 3 | -1 |
| 4 | 2 |
| 5 | 0 |
| 6 | -20 |
| 7 | 100 |
| 8 | -180 |
| 9 | -1540 |
| 10 | 18800 |
| 11 | -99900 |
| 12 | -35000 |
| 13 | 6978400 |
| 14 | -81010800 |
| 15 | 418106000 |
| 16 | 2652650000 |
| 17 | -89962470000 |
| 18 | 1078639120000 |
| 19 | -4572607130000 |
| 20 | -102140361180000 |
| 21 | 2809462217120000 |
| 22 | -34739768494600000 |
| 23 | 80549366231880000 |
| 24 | 7017075372032440000 |
[1,1,0,-1,2,0,-20,100,-180,-1540,18800,-99900, -35000,6978400,-81010800,418106000,2652650000, -89962470000,1078639120000,-4572607130000, -102140361180000,2809462217120000, -34739768494600000,80549366231880000, 7017075372032440000] |