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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 288 |
| 6 | 2112 |
| 7 | 11928 |
| 8 | 66192 |
| 9 | 353544 |
| 10 | 1817208 |
| 11 | 9092592 |
| 12 | 44547912 |
| 13 | 214532136 |
| 14 | 1019264736 |
| 15 | 4783813296 |
| 16 | 22238211480 |
| 17 | 102424615968 |
| 18 | 468396156360 |
[0,0,0,0,288,2112,11928,66192,353544,1817208, 9092592,44547912,214532136,1019264736,4783813296, 22238211480,102424615968,468396156360] |