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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 4 |
| 3 | 8 |
| 4 | 24 |
| 5 | 80 |
| 6 | 288 |
| 7 | 1088 |
| 8 | 4256 |
| 9 | 17088 |
| 10 | 70016 |
| 11 | 291584 |
| 12 | 1230592 |
| 13 | 5251584 |
| 14 | 22623232 |
| 15 | 98248704 |
| 16 | 429677056 |
| 17 | 1890700288 |
| 18 | 8364824576 |
| 19 | 37186449408 |
| 20 | 166030266368 |
| 21 | 744180244480 |
| 22 | 3347321831424 |
| 23 | 15104525959168 |
| 24 | 68357598756864 |
[1,2,4,8,24,80,288,1088,4256,17088,70016,291584, 1230592,5251584,22623232,98248704,429677056, 1890700288,8364824576,37186449408,166030266368, 744180244480,3347321831424,15104525959168, 68357598756864] |