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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 13 |
| 3 | 244 |
| 4 | 6676 |
| 5 | 254736 |
| 6 | 13000464 |
| 7 | 857431296 |
| 8 | 71077637376 |
| 9 | 7239445632000 |
| 10 | 889141110912000 |
| 11 | 129629670893568000 |
| 12 | 22136856913815552000 |
| 13 | 4377599743151480832000 |
| 14 | 992559996665635184640000 |
| 15 | 255805371399126806691840000 |
[1,13,244,6676,254736,13000464,857431296, 71077637376,7239445632000,889141110912000, 129629670893568000,22136856913815552000, 4377599743151480832000,992559996665635184640000, 255805371399126806691840000] |