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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 2 |
| 4 | 56 |
| 5 | 3488 |
| 6 | 664688 |
| 7 | 434127152 |
| 8 | 1019647579136 |
| 9 | 8819902136934912 |
| 10 | 284798318582888580608 |
| 11 | 34636901578294133260750592 |
| 12 | 15970288165992077917878979939328 |
| 13 | 28060652850285225214988677641875677184 |
| 14 | 188680826646319054103468721801532834939660288 |
[0,0,2,56,3488,664688,434127152,1019647579136, 8819902136934912,284798318582888580608, 34636901578294133260750592, 15970288165992077917878979939328, 28060652850285225214988677641875677184, 188680826646319054103468721801532834939660288] |