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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 11 |
| 4 | 48 |
| 5 | 158 |
| 6 | 716 |
| 7 | 2573 |
| 8 | 12062 |
| 9 | 45986 |
| 10 | 217794 |
| 11 | 859062 |
| 12 | 4122214 |
| 13 | 16719152 |
| 14 | 80603908 |
| 15 | 333063447 |
| 16 | 1616114454 |
| 17 | 6786750602 |
| 18 | 33020872398 |
| 19 | 140310630492 |
| 20 | 685241305096 |
| 21 | 2942592127670 |
| 22 | 14396581502884 |
| 23 | 62328036927798 |
| 24 | 305671667504844 |
| 25 | 1333257556909248 |
| 26 | 6546913161612528 |
| 27 | 28727562533188744 |
[1,1,4,11,48,158,716,2573,12062,45986,217794, 859062,4122214,16719152,80603908,333063447, 1616114454,6786750602,33020872398,140310630492, 685241305096,2942592127670,14396581502884, 62328036927798,305671667504844,1333257556909248, 6546913161612528,28727562533188744] |