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| n | a(n) |
|---|---|
| 0 | -1 |
| 1 | -1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 6 |
| 5 | 29 |
| 6 | 150 |
| 7 | 841 |
| 8 | 5166 |
| 9 | 34649 |
| 10 | 252750 |
| 11 | 1995181 |
| 12 | 16962726 |
| 13 | 154624469 |
| 14 | 1505035350 |
| 15 | 15583997521 |
| 16 | 171082318686 |
| 17 | 1985148989489 |
| 18 | 24279125761950 |
| 19 | 312193418011861 |
| 20 | 4210755676649046 |
| 21 | 59445878286889709 |
| 22 | 876726137720576550 |
| 23 | 13483686390543382201 |
[-1,-1,0,1,6,29,150,841,5166,34649,252750,1995181, 16962726,154624469,1505035350,15583997521, 171082318686,1985148989489,24279125761950, 312193418011861,4210755676649046, 59445878286889709,876726137720576550, 13483686390543382201] |