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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 10 |
| 5 | 24 |
| 6 | 144 |
| 7 | 376 |
| 8 | 2472 |
| 9 | 6752 |
| 10 | 46816 |
| 11 | 131456 |
| 12 | 943552 |
| 13 | 2699264 |
| 14 | 19850368 |
| 15 | 57553280 |
| 16 | 430913152 |
| 17 | 1262056960 |
| 18 | 9580742144 |
| 19 | 28282194944 |
| 20 | 217067031552 |
| 21 | 644844589056 |
| 22 | 4993494147072 |
| 23 | 14911395631104 |
| 24 | 116325175037952 |
| 25 | 348873398829056 |
| 26 | 2738566237405184 |
| 27 | 8243483715649536 |
| 28 | 65053575212630016 |
[1,1,2,10,24,144,376,2472,6752,46816,131456, 943552,2699264,19850368,57553280,430913152, 1262056960,9580742144,28282194944,217067031552, 644844589056,4993494147072,14911395631104, 116325175037952,348873398829056,2738566237405184, 8243483715649536,65053575212630016] |