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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 80 |
| 2 | 3200 |
| 3 | 85360 |
| 4 | 1708800 |
| 5 | 27392016 |
| 6 | 366366080 |
| 7 | 4206606640 |
| 8 | 42340840960 |
| 9 | 379634835920 |
| 10 | 3070951360128 |
| 11 | 22644802030320 |
| 12 | 153524473002240 |
| 13 | 963926974039440 |
| 14 | 5639746542798720 |
| 15 | 30914051605760688 |
| 16 | 159505036253752320 |
| 17 | 777889039669799760 |
| 18 | 3599066875202445440 |
| 19 | 15849971773188538480 |
[1,80,3200,85360,1708800,27392016,366366080, 4206606640,42340840960,379634835920,3070951360128, 22644802030320,153524473002240,963926974039440, 5639746542798720,30914051605760688, 159505036253752320,777889039669799760, 3599066875202445440,15849971773188538480] |