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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 15 |
| 5 | 44 |
| 6 | 147 |
| 7 | 495 |
| 8 | 1758 |
| 9 | 6392 |
| 10 | 23877 |
| 11 | 90960 |
| 12 | 352682 |
| 13 | 1388471 |
| 14 | 5536070 |
| 15 | 22333566 |
| 16 | 90999168 |
| 17 | 374144507 |
| 18 | 1550788644 |
| 19 | 6474314495 |
| 20 | 27208663317 |
| 21 | 115026686024 |
| 22 | 488951418197 |
| 23 | 2088810690352 |
| 24 | 8964559511261 |
| 25 | 38636855716466 |
| 26 | 167177656758582 |
| 27 | 726003687715148 |
| 28 | 3163527887839747 |
[1,1,2,5,15,44,147,495,1758,6392,23877,90960, 352682,1388471,5536070,22333566,90999168, 374144507,1550788644,6474314495,27208663317, 115026686024,488951418197,2088810690352, 8964559511261,38636855716466,167177656758582, 726003687715148,3163527887839747] |