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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 12 |
| 5 | 33 |
| 6 | 109 |
| 7 | 342 |
| 8 | 1226 |
| 9 | 4201 |
| 10 | 15742 |
| 11 | 57080 |
| 12 | 221634 |
| 13 | 837409 |
| 14 | 3332844 |
| 15 | 12983589 |
| 16 | 52719344 |
| 17 | 210307546 |
| 18 | 867369706 |
| 19 | 3526066972 |
| 20 | 14731903807 |
| 21 | 60815029670 |
| 22 | 256818485041 |
| 23 | 1073752848245 |
| 24 | 4575811278716 |
| 25 | 19337011492356 |
| 26 | 83048998903207 |
| 27 | 354171226561322 |
| 28 | 1531417121693314 |
| 29 | 6582338524938034 |
[1,1,2,4,12,33,109,342,1226,4201,15742,57080, 221634,837409,3332844,12983589,52719344,210307546, 867369706,3526066972,14731903807,60815029670, 256818485041,1073752848245,4575811278716, 19337011492356,83048998903207,354171226561322, 1531417121693314,6582338524938034] |