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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 3 |
| 3 | 10 |
| 4 | 21 |
| 5 | 110 |
| 6 | 273 |
| 7 | 1870 |
| 8 | 5187 |
| 9 | 43010 |
| 10 | 150423 |
| 11 | 1333310 |
| 12 | 5565651 |
| 13 | 54665710 |
| 14 | 239322993 |
| 15 | 2569288370 |
| 16 | 12684118629 |
| 17 | 151588013830 |
| 18 | 773731236369 |
| 19 | 10156396926610 |
| 20 | 54934917782199 |
| 21 | 741416975642530 |
| 22 | 4339858504793721 |
[1,2,3,10,21,110,273,1870,5187,43010,150423, 1333310,5565651,54665710,239322993,2569288370, 12684118629,151588013830,773731236369, 10156396926610,54934917782199,741416975642530, 4339858504793721] |