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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 19 |
| 6 | 84 |
| 7 | 393 |
| 8 | 1865 |
| 9 | 8886 |
| 10 | 42381 |
| 11 | 202187 |
| 12 | 964640 |
| 13 | 4602409 |
| 14 | 21958729 |
| 15 | 104768258 |
| 16 | 499864605 |
| 17 | 2384926971 |
| 18 | 11378834836 |
| 19 | 54290082897 |
| 20 | 259025915025 |
| 21 | 1235850473974 |
| 22 | 5896423120549 |
| 23 | 28132695944723 |
| 24 | 134225201438720 |
[0,1,1,2,5,19,84,393,1865,8886,42381,202187, 964640,4602409,21958729,104768258,499864605, 2384926971,11378834836,54290082897,259025915025, 1235850473974,5896423120549,28132695944723, 134225201438720] |