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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 10 |
| 4 | 33 |
| 5 | 115 |
| 6 | 391 |
| 7 | 1439 |
| 8 | 5405 |
| 9 | 20303 |
| 10 | 79050 |
| 11 | 311520 |
| 12 | 1230961 |
| 13 | 4964657 |
| 14 | 20189652 |
| 15 | 82314358 |
| 16 | 340130593 |
| 17 | 1413947795 |
| 18 | 5890309480 |
| 19 | 24773921096 |
| 20 | 104674234969 |
| 21 | 443030309859 |
| 22 | 1888676636461 |
| 23 | 8080601115239 |
| 24 | 34621402879031 |
| 25 | 149177215251621 |
| 26 | 644645021479230 |
| 27 | 2789004825787100 |
| 28 | 12121746816861675 |
[1,1,4,10,33,115,391,1439,5405,20303,79050,311520, 1230961,4964657,20189652,82314358,340130593, 1413947795,5890309480,24773921096,104674234969, 443030309859,1888676636461,8080601115239, 34621402879031,149177215251621,644645021479230, 2789004825787100,12121746816861675] |