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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 22 |
| 6 | 95 |
| 7 | 450 |
| 8 | 2461 |
| 9 | 14654 |
| 10 | 93851 |
| 11 | 647746 |
| 12 | 4781801 |
| 13 | 37488462 |
| 14 | 310842127 |
| 15 | 2716308194 |
| 16 | 24929090357 |
| 17 | 239556785086 |
| 18 | 2404139609987 |
| 19 | 25139451248418 |
| 20 | 273330944247265 |
| 21 | 3084182865509966 |
| 22 | 36055337388402935 |
| 23 | 436016786153035522 |
| 24 | 5446585683469420205 |
[1,0,1,2,5,22,95,450,2461,14654,93851,647746, 4781801,37488462,310842127,2716308194,24929090357, 239556785086,2404139609987,25139451248418, 273330944247265,3084182865509966, 36055337388402935,436016786153035522, 5446585683469420205] |