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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 10 |
| 2 | 55 |
| 3 | 220 |
| 4 | 717 |
| 5 | 2032 |
| 6 | 5245 |
| 7 | 12800 |
| 8 | 30433 |
| 9 | 71936 |
| 10 | 170528 |
| 11 | 405140 |
| 12 | 960039 |
| 13 | 2259412 |
| 14 | 5272302 |
| 15 | 12207404 |
| 16 | 28100505 |
| 17 | 64437020 |
| 18 | 147387480 |
| 19 | 336449420 |
| 20 | 766499736 |
| 21 | 1742452890 |
| 22 | 3952091015 |
| 23 | 8944258380 |
| 24 | 20202499027 |
| 25 | 45553242078 |
| 26 | 102561076960 |
| 27 | 230601450120 |
| 28 | 517844031238 |
[1,10,55,220,717,2032,5245,12800,30433,71936, 170528,405140,960039,2259412,5272302,12207404, 28100505,64437020,147387480,336449420,766499736, 1742452890,3952091015,8944258380,20202499027, 45553242078,102561076960,230601450120, 517844031238] |