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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 16 |
| 5 | 52 |
| 6 | 208 |
| 7 | 800 |
| 8 | 2900 |
| 9 | 10960 |
| 10 | 40792 |
| 11 | 148288 |
| 12 | 544600 |
| 13 | 2000084 |
| 14 | 7312332 |
| 15 | 26795812 |
| 16 | 98234356 |
| 17 | 359845004 |
| 18 | 1319030780 |
| 19 | 4834945864 |
| 20 | 17718152672 |
| 21 | 64944710636 |
| 22 | 238041386504 |
| 23 | 872396576888 |
| 24 | 3197533964256 |
| 25 | 11719620057508 |
[1,2,6,16,52,208,800,2900,10960,40792,148288, 544600,2000084,7312332,26795812,98234356, 359845004,1319030780,4834945864,17718152672, 64944710636,238041386504,872396576888, 3197533964256,11719620057508] |