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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 8 |
| 5 | 29 |
| 6 | 88 |
| 7 | 253 |
| 8 | 775 |
| 9 | 2575 |
| 10 | 8797 |
| 11 | 29833 |
| 12 | 100635 |
| 13 | 342408 |
| 14 | 1181727 |
| 15 | 4120223 |
| 16 | 14435969 |
| 17 | 50738813 |
| 18 | 179038408 |
| 19 | 634696939 |
| 20 | 2259677734 |
| 21 | 8072923814 |
| 22 | 28924907573 |
| 23 | 103915759961 |
| 24 | 374302237154 |
| 25 | 1351541722226 |
| 26 | 4891132336481 |
| 27 | 17736792240766 |
| 28 | 64440831300682 |
[1,1,1,2,8,29,88,253,775,2575,8797,29833,100635, 342408,1181727,4120223,14435969,50738813, 179038408,634696939,2259677734,8072923814, 28924907573,103915759961,374302237154, 1351541722226,4891132336481,17736792240766, 64440831300682] |