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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 6 |
| 4 | 17 |
| 5 | 43 |
| 6 | 140 |
| 7 | 430 |
| 8 | 1447 |
| 9 | 4868 |
| 10 | 16841 |
| 11 | 58787 |
| 12 | 208166 |
| 13 | 742901 |
| 14 | 2674872 |
| 15 | 9694893 |
| 16 | 35359117 |
| 17 | 129644791 |
| 18 | 477643702 |
| 19 | 1767263191 |
| 20 | 6564137275 |
| 21 | 24466267455 |
| 22 | 91482622429 |
| 23 | 343059613651 |
| 24 | 1289904356920 |
| 25 | 4861946401495 |
| 26 | 18367353815055 |
| 27 | 69533550920872 |
[1,3,6,17,43,140,430,1447,4868,16841,58787,208166, 742901,2674872,9694893,35359117,129644791, 477643702,1767263191,6564137275,24466267455, 91482622429,343059613651,1289904356920, 4861946401495,18367353815055,69533550920872] |