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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 9 |
| 3 | 41 |
| 4 | 203 |
| 5 | 1216 |
| 6 | 8144 |
| 7 | 58622 |
| 8 | 440258 |
| 9 | 3424680 |
| 10 | 27409999 |
| 11 | 224373161 |
| 12 | 1870585459 |
| 13 | 15834656003 |
| 14 | 135779962760 |
| 15 | 1177207270204 |
[2,9,41,203,1216,8144,58622,440258,3424680, 27409999,224373161,1870585459,15834656003, 135779962760,1177207270204] |