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| n | a(n) |
|---|---|
| 4 | 1 |
| 5 | 1 |
| 6 | 3 |
| 7 | 7 |
| 8 | 24 |
| 9 | 74 |
| 10 | 259 |
| 11 | 891 |
| 12 | 3176 |
| 13 | 11326 |
| 14 | 40942 |
| 15 | 148646 |
| 16 | 543515 |
| 17 | 1996212 |
| 18 | 7367075 |
| 19 | 27294355 |
| 20 | 101501266 |
| 21 | 378701686 |
| 22 | 1417263770 |
| 23 | 5318762098 |
| 24 | 20011847548 |
| 25 | 75473144396 |
| 26 | 285267393358 |
| 27 | 1080432637662 |
| 28 | 4099856060808 |
| 29 | 15585106611244 |
| 30 | 59343290815356 |
[1,1,3,7,24,74,259,891,3176,11326,40942,148646, 543515,1996212,7367075,27294355,101501266, 378701686,1417263770,5318762098,20011847548, 75473144396,285267393358,1080432637662, 4099856060808,15585106611244,59343290815356] |