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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 4 |
| 5 | 9 |
| 6 | 23 |
| 7 | 65 |
| 8 | 199 |
| 9 | 654 |
| 10 | 2296 |
| 11 | 8568 |
| 12 | 33794 |
| 13 | 140039 |
| 14 | 605869 |
| 15 | 2718531 |
| 16 | 12564289 |
| 17 | 59419764 |
| 18 | 285878342 |
| 19 | 1392536354 |
| 20 | 6842206084 |
| 21 | 33819153429 |
| 22 | 167827213315 |
| 23 | 835048228437 |
| 24 | 4162123757579 |
| 25 | 20768689294634 |
| 26 | 103709892420388 |
[1,1,2,4,9,23,65,199,654,2296,8568,33794,140039, 605869,2718531,12564289,59419764,285878342, 1392536354,6842206084,33819153429,167827213315, 835048228437,4162123757579,20768689294634, 103709892420388] |