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| n | a(n) |
|---|---|
| 3 | 1 |
| 4 | 8 |
| 5 | 54 |
| 6 | 368 |
| 7 | 2649 |
| 8 | 20544 |
| 9 | 172596 |
| 10 | 1569408 |
| 11 | 15398829 |
| 12 | 162412416 |
| 13 | 1834081890 |
| 14 | 22093090560 |
| 15 | 282889238253 |
| 16 | 3837991053312 |
| 17 | 55010010678120 |
| 18 | 830731742908416 |
| 19 | 13185328329110745 |
| 20 | 219457733809563648 |
| 21 | 3822426663111579150 |
| 22 | 69538569862816419840 |
| 23 | 1318999546575572747265 |
[1,8,54,368,2649,20544,172596,1569408,15398829, 162412416,1834081890,22093090560,282889238253, 3837991053312,55010010678120,830731742908416, 13185328329110745,219457733809563648, 3822426663111579150,69538569862816419840, 1318999546575572747265] |