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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 2 |
| 3 | 54 |
| 4 | 2534 |
| 5 | 186030 |
| 6 | 19794662 |
| 7 | 2885980734 |
| 8 | 552803552534 |
| 9 | 134687987183790 |
| 10 | 40686498089484422 |
| 11 | 14925683377452413214 |
| 12 | 6536580413039406774134 |
| 13 | 3368723388994026165415950 |
| 14 | 2018248855531992511720945382 |
| 15 | 1390953089533285777007059354494 |
| 16 | 1092714503596231472933813958469334 |
[1,0,2,54,2534,186030,19794662,2885980734, 552803552534,134687987183790,40686498089484422, 14925683377452413214,6536580413039406774134, 3368723388994026165415950, 2018248855531992511720945382, 1390953089533285777007059354494, 1092714503596231472933813958469334] |