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| n | a(n) |
|---|---|
| 3 | 1 |
| 4 | 45 |
| 5 | 1131 |
| 6 | 23611 |
| 7 | 461154 |
| 8 | 8837823 |
| 9 | 169844455 |
| 10 | 3307239364 |
| 11 | 65559881608 |
| 12 | 1325285983528 |
| 13 | 27321430823064 |
| 14 | 573932303529170 |
| 15 | 12269791047231748 |
| 16 | 266575464412874571 |
| 17 | 5877527995117635663 |
| 18 | 131334452330324176828 |
| 19 | 2970563969803965041900 |
| 20 | 67935408457473145627500 |
[1,45,1131,23611,461154,8837823,169844455, 3307239364,65559881608,1325285983528, 27321430823064,573932303529170,12269791047231748, 266575464412874571,5877527995117635663, 131334452330324176828,2970563969803965041900, 67935408457473145627500] |