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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 8 |
| 3 | 44 |
| 4 | 280 |
| 5 | 2016 |
| 6 | 15574 |
| 7 | 115168 |
| 8 | 728078 |
| 9 | 3793342 |
| 10 | 16517460 |
| 11 | 61759798 |
| 12 | 203474642 |
| 13 | 603403128 |
| 14 | 1638153030 |
| 15 | 4126393250 |
| 16 | 9747403504 |
| 17 | 21778931370 |
| 18 | 46349684784 |
| 19 | 94496712184 |
| 20 | 185448946836 |
| 21 | 351735813872 |
| 22 | 646956766742 |
| 23 | 1157359269036 |
[2,8,44,280,2016,15574,115168,728078,3793342, 16517460,61759798,203474642,603403128,1638153030, 4126393250,9747403504,21778931370,46349684784, 94496712184,185448946836,351735813872, 646956766742,1157359269036] |