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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 3 |
| 3 | -6 |
| 4 | 3 |
| 5 | 57 |
| 6 | -141 |
| 7 | -321 |
| 8 | 2460 |
| 9 | -1572 |
| 10 | -29400 |
| 11 | 92505 |
| 12 | 196905 |
| 13 | -1841208 |
| 14 | 1608636 |
| 15 | 24028995 |
| 16 | -85167204 |
| 17 | -161127519 |
| 18 | 1756947801 |
| 19 | -1901675715 |
| 20 | -23476298442 |
| 21 | 91225005105 |
| 22 | 149447955855 |
| 23 | -1890518796654 |
| 24 | 2421742054233 |
| 25 | 25239556328043 |
| 26 | -106352841162777 |
[1,3,3,-6,3,57,-141,-321,2460,-1572,-29400,92505, 196905,-1841208,1608636,24028995,-85167204, -161127519,1756947801,-1901675715,-23476298442, 91225005105,149447955855,-1890518796654, 2421742054233,25239556328043,-106352841162777] |