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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 2 |
| 5 | 6 |
| 6 | 10 |
| 7 | 17 |
| 8 | 45 |
| 9 | 153 |
| 10 | 561 |
| 11 | 1670 |
| 12 | 4780 |
| 13 | 14974 |
| 14 | 45555 |
| 15 | 140211 |
| 16 | 419924 |
| 17 | 1245122 |
| 18 | 3669858 |
| 19 | 10724147 |
| 20 | 31185503 |
| 21 | 89840674 |
| 22 | 256746801 |
| 23 | 728672328 |
| 24 | 2051488536 |
| 25 | 5732076608 |
| 26 | 15895090361 |
| 27 | 43752447121 |
| 28 | 119570863227 |
| 29 | 324496444134 |
[1,1,2,2,6,10,17,45,153,561,1670,4780,14974,45555, 140211,419924,1245122,3669858,10724147,31185503, 89840674,256746801,728672328,2051488536, 5732076608,15895090361,43752447121,119570863227, 324496444134] |