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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 27 |
| 5 | 80 |
| 6 | 234 |
| 7 | 677 |
| 8 | 1941 |
| 9 | 5523 |
| 10 | 15615 |
| 11 | 43906 |
| 12 | 122868 |
| 13 | 342409 |
| 14 | 950727 |
| 15 | 2631165 |
| 16 | 7260579 |
| 17 | 19982612 |
| 18 | 54865566 |
| 19 | 150316973 |
| 20 | 411015705 |
| 21 | 1121818311 |
| 22 | 3056773383 |
| 23 | 8316416134 |
| 24 | 22593883752 |
| 25 | 61301547025 |
| 26 | 166118284299 |
| 27 | 449639574897 |
| 28 | 1215751720491 |
| 29 | 3283883157848 |
[0,1,3,9,27,80,234,677,1941,5523,15615,43906, 122868,342409,950727,2631165,7260579,19982612, 54865566,150316973,411015705,1121818311, 3056773383,8316416134,22593883752,61301547025, 166118284299,449639574897,1215751720491, 3283883157848] |