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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 5 |
| 2 | 21 |
| 3 | 76 |
| 4 | 252 |
| 5 | 1108 |
| 6 | 5020 |
| 7 | 21364 |
| 8 | 86476 |
| 9 | 343440 |
| 10 | 1381412 |
| 11 | 5526704 |
| 12 | 22126848 |
| 13 | 88572656 |
| 14 | 354349312 |
| 15 | 1417262424 |
[1,5,21,76,252,1108,5020,21364,86476,343440, 1381412,5526704,22126848,88572656,354349312, 1417262424] |