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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 8 |
| 4 | 26 |
| 5 | 86 |
| 6 | 314 |
| 7 | 1113 |
| 8 | 4239 |
| 9 | 16219 |
| 10 | 63071 |
| 11 | 248619 |
| 12 | 1006515 |
| 13 | 4029015 |
| 14 | 16543263 |
| 15 | 68254132 |
| 16 | 282375694 |
| 17 | 1178569272 |
| 18 | 4977684152 |
| 19 | 20904474572 |
| 20 | 88923131344 |
| 21 | 379777454862 |
| 22 | 1621498075454 |
| 23 | 6967327961546 |
| 24 | 30135682169814 |
| 25 | 129893637023738 |
| 26 | 564250514132646 |
| 27 | 2459005713673728 |
| 28 | 10704199214707220 |
[1,1,3,8,26,86,314,1113,4239,16219,63071,248619, 1006515,4029015,16543263,68254132,282375694, 1178569272,4977684152,20904474572,88923131344, 379777454862,1621498075454,6967327961546, 30135682169814,129893637023738,564250514132646, 2459005713673728,10704199214707220] |