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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 8 |
| 4 | 28 |
| 5 | 91 |
| 6 | 352 |
| 7 | 1306 |
| 8 | 5182 |
| 9 | 20797 |
| 10 | 85424 |
| 11 | 355119 |
| 12 | 1504967 |
| 13 | 6418859 |
| 14 | 27758070 |
| 15 | 120917363 |
| 16 | 531015804 |
| 17 | 2349303542 |
| 18 | 10455790760 |
| 19 | 46802437636 |
| 20 | 210614263933 |
| 21 | 951984893677 |
| 22 | 4322352594813 |
| 23 | 19700431190212 |
| 24 | 90116118871500 |
| 25 | 413622990248458 |
| 26 | 1904276004073268 |
| 27 | 8792668328752535 |
| 28 | 40707759528449518 |
[1,1,3,8,28,91,352,1306,5182,20797,85424,355119, 1504967,6418859,27758070,120917363,531015804, 2349303542,10455790760,46802437636,210614263933, 951984893677,4322352594813,19700431190212, 90116118871500,413622990248458,1904276004073268, 8792668328752535,40707759528449518] |