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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 24 |
| 5 | 96 |
| 6 | 504 |
| 7 | 3216 |
| 8 | 24024 |
| 9 | 205056 |
| 10 | 1965624 |
| 11 | 20886576 |
| 12 | 243511704 |
| 13 | 3089233056 |
| 14 | 42351635064 |
| 15 | 623815221456 |
| 16 | 9823096307544 |
| 17 | 164655323578176 |
| 18 | 2926840752827064 |
| 19 | 54988308080981616 |
| 20 | 1088680464831056664 |
| 21 | 22653422225916839136 |
| 22 | 494229434646381585144 |
| 23 | 11280809162286897977616 |
[0,0,0,24,96,504,3216,24024,205056,1965624, 20886576,243511704,3089233056,42351635064, 623815221456,9823096307544,164655323578176, 2926840752827064,54988308080981616, 1088680464831056664,22653422225916839136, 494229434646381585144,11280809162286897977616] |