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| n | a(n) |
|---|---|
| 1 | 54 |
| 2 | 3220 |
| 3 | 38794 |
| 4 | 237832 |
| 5 | 995710 |
| 6 | 3256540 |
| 7 | 8954258 |
| 8 | 21645200 |
| 9 | 47366982 |
| 10 | 95758500 |
| 11 | 181475866 |
| 12 | 325939096 |
| 13 | 559444366 |
| 14 | 923676652 |
| 15 | 1474657570 |
| 16 | 2286163232 |
| 17 | 3453646934 |
| 18 | 5098701492 |
| 19 | 7374096042 |
| 20 | 10469422120 |
| 21 | 14617383838 |
[54,3220,38794,237832,995710,3256540,8954258, 21645200,47366982,95758500,181475866,325939096, 559444366,923676652,1474657570,2286163232, 3453646934,5098701492,7374096042,10469422120, 14617383838] |