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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 33 |
| 5 | 119 |
| 6 | 454 |
| 7 | 1779 |
| 8 | 7152 |
| 9 | 29311 |
| 10 | 122013 |
| 11 | 514390 |
| 12 | 2192976 |
| 13 | 9435593 |
| 14 | 40927132 |
| 15 | 178767188 |
| 16 | 785677788 |
| 17 | 3471969333 |
| 18 | 15417894851 |
| 19 | 68766083151 |
| 20 | 307921250078 |
| 21 | 1383758689713 |
| 22 | 6238746051177 |
| 23 | 28211698413079 |
| 24 | 127923279261484 |
| 25 | 581519329356110 |
| 26 | 2649655569254817 |
| 27 | 12099042388429222 |
| 28 | 55358244255747829 |
[1,1,3,9,33,119,454,1779,7152,29311,122013,514390, 2192976,9435593,40927132,178767188,785677788, 3471969333,15417894851,68766083151,307921250078, 1383758689713,6238746051177,28211698413079, 127923279261484,581519329356110,2649655569254817, 12099042388429222,55358244255747829] |