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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 8 |
| 6 | 9862 |
| 7 | 1067638 |
| 8 | 55488142 |
| 9 | 3374967940 |
| 10 | 239187240144 |
| 11 | 15360134570696 |
| 12 | 964730606632516 |
| 13 | 61989683445413228 |
| 14 | 4005716717182224826 |
| 15 | 255967892553030600920 |
| 16 | 16378998506224697063588 |
| 17 | 1050504687249683771795632 |
| 18 | 67351449674771471216148786 |
| 19 | 4314151246752166099728445868 |
[0,0,0,0,8,9862,1067638,55488142,3374967940, 239187240144,15360134570696,964730606632516, 61989683445413228,4005716717182224826, 255967892553030600920,16378998506224697063588, 1050504687249683771795632, 67351449674771471216148786, 4314151246752166099728445868] |