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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 104 |
| 6 | 592 |
| 7 | 3384 |
| 8 | 22544 |
| 9 | 172448 |
| 10 | 1468904 |
| 11 | 13506934 |
| 12 | 134335588 |
| 13 | 1414062686 |
| 14 | 16456846630 |
| 15 | 203601501758 |
| 16 | 2712671491944 |
[1,2,6,24,104,592,3384,22544,172448,1468904, 13506934,134335588,1414062686,16456846630, 203601501758,2712671491944] |