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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 21 |
| 4 | 83 |
| 5 | 363 |
| 6 | 1733 |
| 7 | 8942 |
| 8 | 49484 |
| 9 | 291871 |
| 10 | 1825501 |
| 11 | 12054705 |
| 12 | 83734241 |
| 13 | 609851830 |
| 14 | 4644041462 |
| 15 | 36883843101 |
| 16 | 304846039251 |
| 17 | 2616765134351 |
| 18 | 23286746418237 |
| 19 | 214489200063218 |
| 20 | 2041785040262972 |
| 21 | 20060079966396887 |
| 22 | 203156789589084133 |
| 23 | 2118391734395139205 |
[1,2,6,21,83,363,1733,8942,49484,291871,1825501, 12054705,83734241,609851830,4644041462, 36883843101,304846039251,2616765134351, 23286746418237,214489200063218,2041785040262972, 20060079966396887,203156789589084133, 2118391734395139205] |