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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 2 |
| 2 | -1 |
| 3 | -16 |
| 4 | 42 |
| 5 | 492 |
| 6 | -3210 |
| 7 | -30168 |
| 8 | 404264 |
| 9 | 2783952 |
| 10 | -75206520 |
| 11 | -292604288 |
| 12 | 19217701008 |
| 13 | 3111794272 |
| 14 | -6389076941520 |
| 15 | 29520888356032 |
| 16 | 2643629755167360 |
| 17 | -29037077579992832 |
| 18 | -1307061634619873664 |
[0,2,-1,-16,42,492,-3210,-30168,404264,2783952, -75206520,-292604288,19217701008,3111794272, -6389076941520,29520888356032,2643629755167360, -29037077579992832,-1307061634619873664] |