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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 8 |
| 3 | 32 |
| 4 | 138 |
| 5 | 616 |
| 6 | 2816 |
| 7 | 13108 |
| 8 | 61764 |
| 9 | 293968 |
| 10 | 1409604 |
| 11 | 6800654 |
| 12 | 32970232 |
| 13 | 160487760 |
| 14 | 783813576 |
| 15 | 3838839984 |
| 16 | 18845981576 |
| 17 | 92707895520 |
| 18 | 456847371156 |
| 19 | 2254651625402 |
| 20 | 11141837104710 |
| 21 | 55122849299652 |
| 22 | 272988026623936 |
| 23 | 1353135158061896 |
| 24 | 6712438835266828 |
| 25 | 33321394925379744 |
| 26 | 165514812006856556 |
[1,2,8,32,138,616,2816,13108,61764,293968,1409604, 6800654,32970232,160487760,783813576,3838839984, 18845981576,92707895520,456847371156, 2254651625402,11141837104710,55122849299652, 272988026623936,1353135158061896,6712438835266828, 33321394925379744,165514812006856556] |