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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 19 |
| 5 | 66 |
| 6 | 227 |
| 7 | 851 |
| 8 | 3164 |
| 9 | 11706 |
| 10 | 44397 |
| 11 | 168814 |
| 12 | 641641 |
| 13 | 2460264 |
| 14 | 9462675 |
| 15 | 36434340 |
| 16 | 140822588 |
| 17 | 545555490 |
| 18 | 2116273293 |
| 19 | 8226372157 |
| 20 | 32029990809 |
| 21 | 124856742546 |
| 22 | 487360876726 |
| 23 | 1904604296103 |
| 24 | 7450351584876 |
| 25 | 29172240231616 |
[1,1,2,5,19,66,227,851,3164,11706,44397,168814, 641641,2460264,9462675,36434340,140822588, 545555490,2116273293,8226372157,32029990809, 124856742546,487360876726,1904604296103, 7450351584876,29172240231616] |