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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 27 |
| 4 | 257 |
| 5 | 3189 |
| 6 | 48843 |
| 7 | 889079 |
| 8 | 18730597 |
| 9 | 447945714 |
| 10 | 11983618199 |
| 11 | 354519428597 |
| 12 | 11490618543066 |
| 13 | 404910044246256 |
| 14 | 15412461332440829 |
| 15 | 630199633730994675 |
| 16 | 27548323149955792880 |
| 17 | 1282044807268698303751 |
| 18 | 63284535745130267484867 |
[1,1,4,27,257,3189,48843,889079,18730597, 447945714,11983618199,354519428597,11490618543066, 404910044246256,15412461332440829, 630199633730994675,27548323149955792880, 1282044807268698303751,63284535745130267484867] |