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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 5 |
| 4 | 18 |
| 5 | 69 |
| 6 | 245 |
| 7 | 923 |
| 8 | 3412 |
| 9 | 12864 |
| 10 | 48549 |
| 11 | 184755 |
| 12 | 705162 |
| 13 | 2704155 |
| 14 | 10399675 |
| 15 | 40116525 |
| 16 | 155114088 |
| 17 | 601080389 |
| 18 | 2333593104 |
| 19 | 9075135299 |
| 20 | 35345215162 |
| 21 | 137846527891 |
| 22 | 538257689683 |
| 23 | 2104098963719 |
| 24 | 8233430018756 |
| 25 | 32247603683030 |
[1,1,5,18,69,245,923,3412,12864,48549,184755, 705162,2704155,10399675,40116525,155114088, 601080389,2333593104,9075135299,35345215162, 137846527891,538257689683,2104098963719, 8233430018756,32247603683030] |