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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 4 |
| 5 | 9 |
| 6 | 20 |
| 7 | 48 |
| 8 | 114 |
| 9 | 283 |
| 10 | 709 |
| 11 | 1806 |
| 12 | 4626 |
| 13 | 11940 |
| 14 | 30880 |
| 15 | 80055 |
| 16 | 207586 |
| 17 | 538330 |
| 18 | 1395080 |
| 19 | 3612756 |
| 20 | 9346541 |
| 21 | 24157618 |
| 22 | 62377353 |
| 23 | 160914843 |
| 24 | 414737061 |
| 25 | 1068032468 |
| 26 | 2748211066 |
| 27 | 7066320945 |
| 28 | 18156540077 |
| 29 | 46621728265 |
| 30 | 119639668421 |
[1,1,1,2,4,9,20,48,114,283,709,1806,4626,11940, 30880,80055,207586,538330,1395080,3612756,9346541, 24157618,62377353,160914843,414737061,1068032468, 2748211066,7066320945,18156540077,46621728265, 119639668421] |