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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 6 |
| 5 | 22 |
| 6 | 95 |
| 7 | 463 |
| 8 | 2483 |
| 9 | 14426 |
| 10 | 89799 |
| 11 | 594038 |
| 12 | 4150514 |
| 13 | 30482791 |
| 14 | 234428282 |
| 15 | 1881944298 |
| 16 | 15729230166 |
| 17 | 136566166388 |
| 18 | 1229346044429 |
| 19 | 11454129882773 |
| 20 | 110293243452027 |
| 21 | 1096078120808889 |
| 22 | 11227947692444477 |
| 23 | 118421577443291274 |
| 24 | 1284625091089249880 |
[1,1,1,2,6,22,95,463,2483,14426,89799,594038, 4150514,30482791,234428282,1881944298,15729230166, 136566166388,1229346044429,11454129882773, 110293243452027,1096078120808889, 11227947692444477,118421577443291274, 1284625091089249880] |