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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 10 |
| 4 | 116 |
| 5 | 2763 |
| 6 | 50676 |
| 7 | 3744758 |
| 8 | 392622102 |
| 9 | 57938084203 |
| 10 | 22881769780910 |
[1,4,10,116,2763,50676,3744758,392622102, 57938084203,22881769780910] |