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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | -2 |
| 3 | 6 |
| 4 | -40 |
| 5 | 320 |
| 6 | -2976 |
| 7 | 35392 |
| 8 | -538112 |
| 9 | 9931392 |
| 10 | -211790080 |
| 11 | 5059784576 |
| 12 | -132643057152 |
| 13 | 3761875287040 |
| 14 | -114501941915648 |
| 15 | 3725395402721280 |
| 16 | -129324055589257216 |
| 17 | 4786638435256696832 |
| 18 | -188785468724361560064 |
| 19 | 7922155381738193944576 |
| 20 | -352740315643746941665280 |
| 21 | 16603695476218208847691776 |
| 22 | -822951583413551750366298112 |
| 23 | 42792449844854211313594597376 |
| 24 | -2327246576567999111735900897280 |
| 25 | 132052357036729088907927420928000 |
[1,-2,6,-40,320,-2976,35392,-538112,9931392, -211790080,5059784576,-132643057152,3761875287040, -114501941915648,3725395402721280, -129324055589257216,4786638435256696832, -188785468724361560064,7922155381738193944576, -352740315643746941665280, 16603695476218208847691776, -822951583413551750366298112, 42792449844854211313594597376, -2327246576567999111735900897280, 132052357036729088907927420928000] |