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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 8 |
| 5 | 16 |
| 6 | 8 |
| 7 | -104 |
| 8 | -960 |
| 9 | -5504 |
| 10 | -22400 |
| 11 | -69376 |
| 12 | 251008 |
| 13 | 5144192 |
| 14 | 53882624 |
| 15 | 431779328 |
| 16 | 2088660992 |
| 17 | 3270959104 |
| 18 | -173107810304 |
| 19 | -2994808352768 |
| 20 | -34807275798528 |
| 21 | -327470564016128 |
| 22 | -1238452597522432 |
| 23 | 13424788329791488 |
[1,1,2,4,8,16,8,-104,-960,-5504,-22400,-69376, 251008,5144192,53882624,431779328,2088660992, 3270959104,-173107810304,-2994808352768, -34807275798528,-327470564016128, -1238452597522432,13424788329791488] |