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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -4 |
| 2 | -24 |
| 3 | -456 |
| 4 | -11264 |
| 5 | -289664 |
| 6 | 3000960 |
| 7 | 2697206272 |
| 8 | 625547980800 |
| 9 | 138214081974272 |
| 10 | 32824743592198144 |
| 11 | 8622090358801989632 |
| 12 | 2517001357223737327616 |
| 13 | 813249999853716681654272 |
| 14 | 288227689418308842574053376 |
| 15 | 110555226159597276214983917568 |
[1,-4,-24,-456,-11264,-289664,3000960,2697206272, 625547980800,138214081974272,32824743592198144, 8622090358801989632,2517001357223737327616, 813249999853716681654272, 288227689418308842574053376, 110555226159597276214983917568] |