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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 16 |
| 5 | 54 |
| 6 | 232 |
| 7 | 936 |
| 8 | 5070 |
| 9 | 28658 |
| 10 | 170392 |
| 11 | 1087848 |
| 12 | 7171828 |
| 13 | 49584912 |
| 14 | 366964014 |
| 15 | 3450377582 |
| 16 | 32284315804 |
[1,2,6,16,54,232,936,5070,28658,170392,1087848, 7171828,49584912,366964014,3450377582,32284315804] |