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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 8 |
| 4 | 23 |
| 5 | 81 |
| 6 | 280 |
| 7 | 961 |
| 8 | 3559 |
| 9 | 13454 |
| 10 | 50692 |
| 11 | 196368 |
| 12 | 776979 |
| 13 | 3070167 |
| 14 | 12268437 |
| 15 | 49815796 |
| 16 | 203119103 |
| 17 | 831940820 |
| 18 | 3442970866 |
| 19 | 14329445203 |
| 20 | 59783757046 |
| 21 | 250943394923 |
| 22 | 1059386977640 |
| 23 | 4484344952953 |
| 24 | 19051650390329 |
| 25 | 81318085577387 |
| 26 | 348069408274893 |
| 27 | 1493378869048524 |
| 28 | 6429188146005489 |
[1,1,3,8,23,81,280,961,3559,13454,50692,196368, 776979,3070167,12268437,49815796,203119103, 831940820,3442970866,14329445203,59783757046, 250943394923,1059386977640,4484344952953, 19051650390329,81318085577387,348069408274893, 1493378869048524,6429188146005489] |