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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | -1 |
| 3 | 3 |
| 4 | -6 |
| 5 | 23 |
| 6 | -150 |
| 7 | 1351 |
| 8 | -12600 |
| 9 | 118187 |
| 10 | -1224720 |
| 11 | 14702941 |
| 12 | -200731608 |
| 13 | 2986886693 |
| 14 | -47352985680 |
| 15 | 800879433355 |
| 16 | -14538372969120 |
| 17 | 282952402841303 |
| 18 | -5862543549637824 |
| 19 | 128430397643505121 |
| 20 | -2964326737589237000 |
| 21 | 71982961886998521617 |
[0,0,-1,3,-6,23,-150,1351,-12600,118187,-1224720, 14702941,-200731608,2986886693,-47352985680, 800879433355,-14538372969120,282952402841303, -5862543549637824,128430397643505121, -2964326737589237000,71982961886998521617] |