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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 5 |
| 5 | 18 |
| 6 | 35 |
| 7 | 136 |
| 8 | 285 |
| 9 | 1155 |
| 10 | 2530 |
| 11 | 10530 |
| 12 | 23751 |
| 13 | 100688 |
| 14 | 231880 |
| 15 | 996336 |
| 16 | 2330445 |
| 17 | 10116873 |
| 18 | 23950355 |
| 19 | 104819165 |
| 20 | 250543370 |
| 21 | 1103722620 |
| 22 | 2658968130 |
| 23 | 11777187240 |
| 24 | 28558343775 |
| 25 | 127067830773 |
| 26 | 309831575760 |
| 27 | 1383914371728 |
| 28 | 3390416787880 |
| 29 | 15194457001440 |
[1,1,1,3,5,18,35,136,285,1155,2530,10530,23751, 100688,231880,996336,2330445,10116873,23950355, 104819165,250543370,1103722620,2658968130, 11777187240,28558343775,127067830773,309831575760, 1383914371728,3390416787880,15194457001440] |