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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 11 |
| 3 | 120 |
| 4 | 2061 |
| 5 | 48918 |
| 6 | 1487151 |
| 7 | 55188108 |
| 8 | 2419385625 |
| 9 | 122367255498 |
| 10 | 7014349322739 |
| 11 | 449405251066368 |
| 12 | 31826192109186789 |
| 13 | 2468711973793223070 |
| 14 | 208159999898813165079 |
| 15 | 18957203713618483723092 |
| 16 | 1854424578467714146269489 |
| 17 | 193922780991931737971748882 |
| 18 | 21588348501840566333913576795 |
[1,2,11,120,2061,48918,1487151,55188108, 2419385625,122367255498,7014349322739, 449405251066368,31826192109186789, 2468711973793223070,208159999898813165079, 18957203713618483723092,1854424578467714146269489, 193922780991931737971748882, 21588348501840566333913576795] |