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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 16 |
| 6 | 57 |
| 7 | 253 |
| 8 | 1060 |
| 9 | 5285 |
| 10 | 28762 |
| 11 | 191263 |
| 12 | 1052276 |
| 13 | 8028450 |
| 14 | 56576192 |
| 15 | 424900240 |
| 16 | 2584010916 |
| 17 | 24952953943 |
| 18 | 178322999025 |
| 19 | 1886474434192 |
| 20 | 15307571683248 |
| 21 | 143131274598786 |
| 22 | 1423606577935925 |
| 23 | 17668243239613767 |
| 24 | 137205093278725072 |
| 25 | 1399239022852163764 |
| 26 | 15774656316828338767 |
[1,1,1,2,5,16,57,253,1060,5285,28762,191263, 1052276,8028450,56576192,424900240,2584010916, 24952953943,178322999025,1886474434192, 15307571683248,143131274598786,1423606577935925, 17668243239613767,137205093278725072, 1399239022852163764,15774656316828338767] |