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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 6 |
| 4 | 20 |
| 5 | 50 |
| 6 | 191 |
| 7 | 541 |
| 8 | 2177 |
| 9 | 6673 |
| 10 | 27348 |
| 11 | 88173 |
| 12 | 371217 |
| 13 | 1243274 |
| 14 | 5322458 |
| 15 | 18365142 |
| 16 | 79290736 |
| 17 | 279861757 |
| 18 | 1221272764 |
| 19 | 4392018743 |
| 20 | 19317981031 |
| 21 | 70580799383 |
| 22 | 311998052691 |
| 23 | 1154903101359 |
| 24 | 5134112863405 |
| 25 | 19220501337271 |
| 26 | 85835703816078 |
| 27 | 324546760823938 |
| 28 | 1454189667602518 |
| 29 | 5545681979668163 |
[1,1,3,6,20,50,191,541,2177,6673,27348,88173, 371217,1243274,5322458,18365142,79290736, 279861757,1221272764,4392018743,19317981031, 70580799383,311998052691,1154903101359, 5134112863405,19220501337271,85835703816078, 324546760823938,1454189667602518,5545681979668163] |