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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 7 |
| 5 | 25 |
| 6 | 108 |
| 7 | 492 |
| 8 | 2431 |
| 9 | 12356 |
| 10 | 65004 |
| 11 | 349276 |
| 12 | 1913919 |
| 13 | 10648905 |
| 14 | 60053535 |
| 15 | 342565090 |
| 16 | 1973928324 |
[1,1,2,7,25,108,492,2431,12356,65004,349276, 1913919,10648905,60053535,342565090,1973928324] |