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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | -2 |
| 3 | -2 |
| 4 | -16 |
| 5 | -24 |
| 6 | 64 |
| 7 | -720 |
| 8 | -23808 |
| 9 | -35840 |
| 10 | 282368 |
| 11 | -3628800 |
| 12 | -75458560 |
| 13 | -479001600 |
| 14 | 5315078144 |
| 15 | -82614884352 |
| 16 | -8601835798528 |
| 17 | -20922789888000 |
| 18 | 321288633450496 |
| 19 | -6402373705728000 |
| 20 | -309168395474436096 |
| 21 | -2379913632645120000 |
| 22 | 46441359567137275904 |
[1,-2,-2,-16,-24,64,-720,-23808,-35840,282368, -3628800,-75458560,-479001600,5315078144, -82614884352,-8601835798528,-20922789888000, 321288633450496,-6402373705728000, -309168395474436096,-2379913632645120000, 46441359567137275904] |