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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 112 |
| 6 | 604 |
| 7 | 3708 |
| 8 | 27704 |
| 9 | 211432 |
| 10 | 1891158 |
| 11 | 18797728 |
| 12 | 191419156 |
| 13 | 2197262096 |
| 14 | 27378984640 |
| 15 | 338911134156 |
| 16 | 4786283287650 |
[1,2,6,24,112,604,3708,27704,211432,1891158, 18797728,191419156,2197262096,27378984640, 338911134156,4786283287650] |