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| n | a(n) |
|---|---|
| 1 | 18 |
| 2 | 200 |
| 3 | 436 |
| 4 | 3916 |
| 5 | 24126 |
| 6 | 197848 |
| 7 | 1559080 |
| 8 | 12424332 |
| 9 | 95711098 |
| 10 | 709795516 |
| 11 | 5002719434 |
| 12 | 33563203028 |
[18,200,436,3916,24126,197848,1559080,12424332, 95711098,709795516,5002719434,33563203028] |