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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 32 |
| 5 | 332 |
| 6 | 6928 |
| 7 | 292334 |
| 8 | 24875760 |
| 9 | 4254812880 |
| 10 | 1459549877168 |
| 11 | 1002824206109916 |
| 12 | 1379081986798078000 |
| 13 | 3794489305535947254732 |
| 14 | 20884859614892223147785056 |
| 15 | 229923086002576723635638394810 |
[1,1,2,6,32,332,6928,292334,24875760,4254812880, 1459549877168,1002824206109916, 1379081986798078000,3794489305535947254732, 20884859614892223147785056, 229923086002576723635638394810] |