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| n | a(n) |
|---|---|
| 1 | 81 |
| 2 | 255 |
| 3 | 770 |
| 4 | 2475 |
| 5 | 7967 |
| 6 | 26320 |
| 7 | 87685 |
| 8 | 296341 |
| 9 | 1009386 |
| 10 | 3469327 |
| 11 | 11995679 |
| 12 | 41723704 |
| 13 | 145746621 |
| 14 | 511140805 |
| 15 | 1798008490 |
| 16 | 6341897735 |
| 17 | 22416736479 |
| 18 | 79385995448 |
| 19 | 281564936853 |
| 20 | 999990174053 |
| 21 | 3555463819754 |
| 22 | 12653797570015 |
[81,255,770,2475,7967,26320,87685,296341,1009386, 3469327,11995679,41723704,145746621,511140805, 1798008490,6341897735,22416736479,79385995448, 281564936853,999990174053,3555463819754, 12653797570015] |