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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 11 |
| 4 | 36 |
| 5 | 114 |
| 6 | 392 |
| 7 | 1319 |
| 8 | 4572 |
| 9 | 15806 |
| 10 | 55800 |
| 11 | 196414 |
| 12 | 698936 |
| 13 | 2488452 |
| 14 | 8935696 |
| 15 | 32093615 |
| 16 | 115879740 |
| 17 | 418874694 |
| 18 | 1520690456 |
| 19 | 5525783450 |
| 20 | 20139817064 |
| 21 | 73488506268 |
| 22 | 268834264688 |
| 23 | 984430431638 |
| 24 | 3611768138328 |
| 25 | 13264952716588 |
| 26 | 48798930171056 |
| 27 | 179686392437468 |
| 28 | 662521532267376 |
| 29 | 2444965457206408 |
[1,1,4,11,36,114,392,1319,4572,15806,55800,196414, 698936,2488452,8935696,32093615,115879740, 418874694,1520690456,5525783450,20139817064, 73488506268,268834264688,984430431638, 3611768138328,13264952716588,48798930171056, 179686392437468,662521532267376,2444965457206408] |