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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 8 |
| 3 | 141 |
| 4 | 3852 |
| 5 | 143460 |
| 6 | 6780642 |
| 7 | 388851960 |
| 8 | 26235133992 |
| 9 | 2036243259648 |
| 10 | 178742696099040 |
| 11 | 17509589369568648 |
| 12 | 1893647907646728120 |
| 13 | 224106838102512869400 |
| 14 | 28809018473999642686584 |
| 15 | 3997516614926297143604760 |
| 16 | 595518793080901690966354368 |
[1,1,8,141,3852,143460,6780642,388851960, 26235133992,2036243259648,178742696099040, 17509589369568648,1893647907646728120, 224106838102512869400,28809018473999642686584, 3997516614926297143604760, 595518793080901690966354368] |