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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 7 |
| 5 | 15 |
| 6 | 35 |
| 7 | 87 |
| 8 | 217 |
| 9 | 547 |
| 10 | 1417 |
| 11 | 3735 |
| 12 | 9911 |
| 13 | 26513 |
| 14 | 71581 |
| 15 | 194681 |
| 16 | 532481 |
| 17 | 1464029 |
| 18 | 4045117 |
| 19 | 11225159 |
| 20 | 31268577 |
| 21 | 87404465 |
| 22 | 245101771 |
| 23 | 689323849 |
| 24 | 1943817227 |
| 25 | 5494808425 |
| 26 | 15568077235 |
| 27 | 44200775239 |
| 28 | 125739619467 |
[1,1,1,3,7,15,35,87,217,547,1417,3735,9911,26513, 71581,194681,532481,1464029,4045117,11225159, 31268577,87404465,245101771,689323849,1943817227, 5494808425,15568077235,44200775239,125739619467] |