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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 10 |
| 3 | 33 |
| 4 | 110 |
| 5 | 369 |
| 6 | 1247 |
| 7 | 4245 |
| 8 | 14558 |
| 9 | 50295 |
| 10 | 175029 |
| 11 | 613467 |
| 12 | 2165100 |
| 13 | 7692345 |
| 14 | 27504600 |
| 15 | 98941185 |
| 16 | 357952580 |
| 17 | 1301960925 |
| 18 | 4759282415 |
| 19 | 17478557925 |
| 20 | 64468072820 |
| 21 | 238736987535 |
| 22 | 887359113700 |
| 23 | 3309489922743 |
| 24 | 12381998910700 |
| 25 | 46460457776739 |
[1,3,10,33,110,369,1247,4245,14558,50295,175029, 613467,2165100,7692345,27504600,98941185, 357952580,1301960925,4759282415,17478557925, 64468072820,238736987535,887359113700, 3309489922743,12381998910700,46460457776739] |