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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 10 |
| 2 | 55 |
| 3 | 230 |
| 4 | 815 |
| 5 | 2562 |
| 6 | 7360 |
| 7 | 19700 |
| 8 | 49755 |
| 9 | 119700 |
| 10 | 276278 |
| 11 | 615130 |
| 12 | 1326965 |
| 13 | 2783360 |
| 14 | 5693305 |
| 15 | 11384326 |
| 16 | 22299655 |
| 17 | 42865280 |
| 18 | 80983060 |
| 19 | 150571340 |
| 20 | 275840009 |
| 21 | 498410280 |
| 22 | 889056835 |
| 23 | 1566896280 |
| 24 | 2730474975 |
| 25 | 4707724814 |
| 26 | 8035618655 |
| 27 | 13586253440 |
| 28 | 22765030080 |
| 29 | 37820087380 |
[1,10,55,230,815,2562,7360,19700,49755,119700, 276278,615130,1326965,2783360,5693305,11384326, 22299655,42865280,80983060,150571340,275840009, 498410280,889056835,1566896280,2730474975, 4707724814,8035618655,13586253440,22765030080, 37820087380] |