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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 21 |
| 5 | 79 |
| 6 | 311 |
| 7 | 1265 |
| 8 | 5275 |
| 9 | 22431 |
| 10 | 96900 |
| 11 | 424068 |
| 12 | 1876143 |
| 13 | 8377299 |
| 14 | 37704042 |
| 15 | 170870106 |
| 16 | 779058843 |
| 17 | 3571051579 |
| 18 | 16447100702 |
| 19 | 76073821946 |
| 20 | 353224531663 |
| 21 | 1645807790529 |
| 22 | 7692793487307 |
| 23 | 36061795278341 |
| 24 | 169498231169821 |
[1,1,2,6,21,79,311,1265,5275,22431,96900,424068, 1876143,8377299,37704042,170870106,779058843, 3571051579,16447100702,76073821946,353224531663, 1645807790529,7692793487307,36061795278341, 169498231169821] |