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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 9 |
| 3 | 28 |
| 4 | 91 |
| 5 | 304 |
| 6 | 1036 |
| 7 | 3586 |
| 8 | 12571 |
| 9 | 44538 |
| 10 | 159222 |
| 11 | 573648 |
| 12 | 2080766 |
| 13 | 7592438 |
| 14 | 27850010 |
| 15 | 102638190 |
| 16 | 379859835 |
| 17 | 1411205250 |
| 18 | 5260849110 |
| 19 | 19673751960 |
| 20 | 73784984490 |
| 21 | 277457327160 |
| 22 | 1045879727568 |
| 23 | 3951343037220 |
| 24 | 14959393005886 |
[1,3,9,28,91,304,1036,3586,12571,44538,159222, 573648,2080766,7592438,27850010,102638190, 379859835,1411205250,5260849110,19673751960, 73784984490,277457327160,1045879727568, 3951343037220,14959393005886] |