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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 5 |
| 4 | 15 |
| 5 | 55 |
| 6 | 220 |
| 7 | 876 |
| 8 | 3645 |
| 9 | 15485 |
| 10 | 66735 |
| 11 | 292155 |
| 12 | 1293456 |
| 13 | 5782320 |
| 14 | 26071435 |
| 15 | 118402495 |
| 16 | 541150155 |
| 17 | 2487204315 |
| 18 | 11488482130 |
| 19 | 53302256250 |
| 20 | 248293549685 |
| 21 | 1160794446445 |
| 22 | 5444674773325 |
| 23 | 25614768620105 |
| 24 | 120837493137460 |
[1,1,1,5,15,55,220,876,3645,15485,66735,292155, 1293456,5782320,26071435,118402495,541150155, 2487204315,11488482130,53302256250,248293549685, 1160794446445,5444674773325,25614768620105, 120837493137460] |