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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 25 |
| 4 | 110 |
| 5 | 462 |
| 6 | 2141 |
| 7 | 9556 |
| 8 | 45541 |
| 9 | 210423 |
| 10 | 1017684 |
| 11 | 4801563 |
| 12 | 23435336 |
| 13 | 112095191 |
| 14 | 550404475 |
| 15 | 2657813608 |
| 16 | 13104268115 |
| 17 | 63714592627 |
| 18 | 315077285841 |
| 19 | 1539826890331 |
| 20 | 7631392805453 |
| 21 | 37442437107747 |
| 22 | 185873645855999 |
| 23 | 914767473468282 |
| 24 | 4546966126158618 |
| 25 | 22432315967942143 |
| 26 | 111615010538402776 |
[1,2,7,25,110,462,2141,9556,45541,210423,1017684, 4801563,23435336,112095191,550404475,2657813608, 13104268115,63714592627,315077285841, 1539826890331,7631392805453,37442437107747, 185873645855999,914767473468282,4546966126158618, 22432315967942143,111615010538402776] |