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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 8 |
| 3 | 68 |
| 4 | 2106 |
| 5 | 223776 |
| 6 | 80532200 |
| 7 | 98945392200 |
| 8 | 421225839051260 |
| 9 | 6310402120912239968 |
| 10 | 337401124757628967733136 |
| 11 | 65171905481441631827737564000 |
| 12 | 45944096973025484590366745753166436 |
[1,3,8,68,2106,223776,80532200,98945392200, 421225839051260,6310402120912239968, 337401124757628967733136, 65171905481441631827737564000, 45944096973025484590366745753166436] |