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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 9 |
| 3 | 27 |
| 4 | 82 |
| 5 | 242 |
| 6 | 736 |
| 7 | 2188 |
| 8 | 6600 |
| 9 | 19736 |
| 10 | 59328 |
| 11 | 177744 |
| 12 | 533728 |
| 13 | 1600160 |
| 14 | 4802560 |
| 15 | 14403520 |
| 16 | 43218816 |
| 17 | 129640064 |
| 18 | 388952832 |
| 19 | 1166793216 |
| 20 | 3500510464 |
| 21 | 10501269248 |
| 22 | 31504332544 |
| 23 | 94511948032 |
| 24 | 283537942272 |
| 25 | 850609632512 |
[1,3,9,27,82,242,736,2188,6600,19736,59328,177744, 533728,1600160,4802560,14403520,43218816, 129640064,388952832,1166793216,3500510464, 10501269248,31504332544,94511948032,283537942272, 850609632512] |