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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 18 |
| 3 | 312 |
| 4 | 8000 |
| 5 | 271770 |
| 6 | 11502162 |
| 7 | 583036832 |
| 8 | 34437042432 |
| 9 | 2322677883330 |
| 10 | 176137593178250 |
| 11 | 14835018315726312 |
| 12 | 1373972097646792800 |
| 13 | 138787120025382437882 |
| 14 | 15184417945878202716450 |
| 15 | 1788809909368939651651200 |
| 16 | 225755544056485027686459392 |
[1,2,18,312,8000,271770,11502162,583036832, 34437042432,2322677883330,176137593178250, 14835018315726312,1373972097646792800, 138787120025382437882,15184417945878202716450, 1788809909368939651651200, 225755544056485027686459392] |