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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 8 |
| 3 | 80 |
| 4 | 4374 |
| 5 | 9800 |
| 6 | 123200 |
| 7 | 336140 |
| 8 | 11859210 |
| 9 | 177182720 |
| 10 | 1611308699 |
| 11 | 3463199999 |
| 12 | 63927525375 |
| 13 | 421138799639 |
| 14 | 1109496723125 |
| 15 | 1453579866024 |
| 16 | 20628591204480 |
| 17 | 31887350832896 |
| 18 | 119089041053696 |
| 19 | 2286831727304144 |
| 20 | 9591468737351909375 |
| 21 | 19316158377073923834000 |
[1,8,80,4374,9800,123200,336140,11859210, 177182720,1611308699,3463199999,63927525375, 421138799639,1109496723125,1453579866024, 20628591204480,31887350832896,119089041053696, 2286831727304144,9591468737351909375, 19316158377073923834000] |