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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 8 |
| 3 | 671 |
| 4 | 15639 |
| 5 | 42159 |
| 6 | 981911 |
| 7 | 77624048 |
| 8 | 1807894920 |
| 9 | 4873553880 |
| 10 | 113507005568 |
| 11 | 8973184757831 |
| 12 | 208989037004319 |
| 13 | 563373081435879 |
| 14 | 13121182828725551 |
| 15 | 1037282211558181688 |
| 16 | 24158714697817430640 |
| 17 | 65124801462951244560 |
| 18 | 1516782492521509296728 |
[0,8,671,15639,42159,981911,77624048,1807894920, 4873553880,113507005568,8973184757831, 208989037004319,563373081435879,13121182828725551, 1037282211558181688,24158714697817430640, 65124801462951244560,1516782492521509296728] |