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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 10 |
| 3 | 25 |
| 4 | 60 |
| 5 | 133 |
| 6 | 284 |
| 7 | 585 |
| 8 | 1175 |
| 9 | 2310 |
| 10 | 4464 |
| 11 | 8502 |
| 12 | 15995 |
| 13 | 29775 |
| 14 | 54920 |
| 15 | 100487 |
| 16 | 182556 |
| 17 | 329555 |
| 18 | 591550 |
| 19 | 1056405 |
| 20 | 1877821 |
| 21 | 3323868 |
| 22 | 5860800 |
| 23 | 10297500 |
| 24 | 18033925 |
| 25 | 31487643 |
| 26 | 54824854 |
| 27 | 95211205 |
| 28 | 164948700 |
[1,3,10,25,60,133,284,585,1175,2310,4464,8502, 15995,29775,54920,100487,182556,329555,591550, 1056405,1877821,3323868,5860800,10297500,18033925, 31487643,54824854,95211205,164948700] |