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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 3376 |
| 5 | 48485 |
| 6 | 333840 |
| 7 | 1856075 |
| 8 | 7075840 |
| 9 | 23676246 |
| 10 | 70756800 |
| 11 | 186940290 |
| 12 | 428464080 |
| 13 | 1006177555 |
| 14 | 2103214736 |
| 15 | 4100587365 |
| 16 | 7898286080 |
| 17 | 14716985020 |
| 18 | 25687264320 |
| 19 | 44467993236 |
| 20 | 73105750320 |
| 21 | 119679027345 |
| 22 | 192873196720 |
[0,0,0,3376,48485,333840,1856075,7075840,23676246, 70756800,186940290,428464080,1006177555, 2103214736,4100587365,7898286080,14716985020, 25687264320,44467993236,73105750320,119679027345, 192873196720] |