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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 1 |
| 6 | 2 |
| 7 | 6 |
| 8 | 16 |
| 9 | 43 |
| 10 | 117 |
| 11 | 305 |
| 12 | 769 |
| 13 | 1907 |
| 14 | 4686 |
| 15 | 11587 |
| 16 | 28580 |
| 17 | 70451 |
| 18 | 172880 |
| 19 | 423629 |
| 20 | 1036332 |
| 21 | 2533559 |
| 22 | 6186635 |
| 23 | 15092985 |
| 24 | 36784586 |
| 25 | 89590410 |
| 26 | 218069921 |
| 27 | 530551804 |
| 28 | 1290218120 |
| 29 | 3136385254 |
| 30 | 7621522229 |
| 31 | 18515039477 |
| 32 | 44966884766 |
| 33 | 109184448962 |
[1,1,0,0,0,1,2,6,16,43,117,305,769,1907,4686, 11587,28580,70451,172880,423629,1036332,2533559, 6186635,15092985,36784586,89590410,218069921, 530551804,1290218120,3136385254,7621522229, 18515039477,44966884766,109184448962] |