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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 14 |
| 5 | 42 |
| 6 | 133 |
| 7 | 433 |
| 8 | 1455 |
| 9 | 4958 |
| 10 | 17247 |
| 11 | 60502 |
| 12 | 215353 |
| 13 | 770865 |
| 14 | 2789365 |
| 15 | 10134529 |
| 16 | 37130526 |
| 17 | 136451349 |
| 18 | 504837219 |
| 19 | 1872121732 |
| 20 | 6980767968 |
| 21 | 26078614284 |
| 22 | 97872756530 |
| 23 | 367861581953 |
| 24 | 1388061197005 |
| 25 | 5243972732886 |
[1,1,2,5,14,42,133,433,1455,4958,17247,60502, 215353,770865,2789365,10134529,37130526,136451349, 504837219,1872121732,6980767968,26078614284, 97872756530,367861581953,1388061197005, 5243972732886] |