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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 5 |
| 3 | 10 |
| 4 | 30 |
| 5 | 55 |
| 6 | 155 |
| 7 | 280 |
| 8 | 780 |
| 9 | 1405 |
| 10 | 3905 |
| 11 | 7030 |
| 12 | 19530 |
| 13 | 35155 |
| 14 | 97655 |
| 15 | 175780 |
| 16 | 488280 |
| 17 | 878905 |
| 18 | 2441405 |
| 19 | 4394530 |
| 20 | 12207030 |
| 21 | 21972655 |
| 22 | 61035155 |
| 23 | 109863280 |
| 24 | 305175780 |
| 25 | 549316405 |
| 26 | 1525878905 |
| 27 | 2746582030 |
| 28 | 7629394530 |
| 29 | 13732910155 |
| 30 | 38146972655 |
| 31 | 68664550780 |
[1,5,10,30,55,155,280,780,1405,3905,7030,19530, 35155,97655,175780,488280,878905,2441405,4394530, 12207030,21972655,61035155,109863280,305175780, 549316405,1525878905,2746582030,7629394530, 13732910155,38146972655,68664550780] |