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| n | a(n) |
|---|---|
| 1 | 6 |
| 2 | 38 |
| 3 | 320 |
| 4 | 2819 |
| 5 | 25668 |
| 6 | 237586 |
| 7 | 2224574 |
| 8 | 21007948 |
| 9 | 199725336 |
| 10 | 1908845614 |
| 11 | 18321586810 |
| 12 | 176478166845 |
[6,38,320,2819,25668,237586,2224574,21007948, 199725336,1908845614,18321586810,176478166845] |