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| n | a(n) |
|---|---|
| 0 | 2 |
| 1 | 9 |
| 2 | 108 |
| 3 | 1848 |
| 4 | 36306 |
| 5 | 771768 |
| 6 | 17280096 |
| 7 | 401451192 |
| 8 | 9587095686 |
| 9 | 233892105912 |
| 10 | 5804193409056 |
| 11 | 146051807458320 |
| 12 | 3717875447707254 |
| 13 | 95571022734750600 |
| 14 | 2477365983601721280 |
| 15 | 64684289495622383472 |
| 16 | 1699638032224106092368 |
| 17 | 44909438746576707103608 |
[2,9,108,1848,36306,771768,17280096,401451192, 9587095686,233892105912,5804193409056, 146051807458320,3717875447707254, 95571022734750600,2477365983601721280, 64684289495622383472,1699638032224106092368, 44909438746576707103608] |