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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 16 |
| 4 | 56 |
| 5 | 176 |
| 6 | 632 |
| 7 | 2080 |
| 8 | 7744 |
| 9 | 26752 |
| 10 | 100352 |
| 11 | 353024 |
| 12 | 1345280 |
| 13 | 4843008 |
| 14 | 18516864 |
| 15 | 67305984 |
| 16 | 259601408 |
| 17 | 956426240 |
| 18 | 3695605760 |
| 19 | 13696663552 |
| 20 | 53218287616 |
| 21 | 198990118912 |
| 22 | 774023897088 |
| 23 | 2905880100864 |
| 24 | 11346564612096 |
| 25 | 42864799645696 |
| 26 | 167495532347392 |
| 27 | 634607654010880 |
| 28 | 2486700816072704 |
[1,2,6,16,56,176,632,2080,7744,26752,100352, 353024,1345280,4843008,18516864,67305984, 259601408,956426240,3695605760,13696663552, 53218287616,198990118912,774023897088, 2905880100864,11346564612096,42864799645696, 167495532347392,634607654010880,2486700816072704] |