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| n | a(n) |
|---|---|
| 5 | 1 |
| 6 | 12 |
| 7 | 90 |
| 8 | 520 |
| 9 | 2535 |
| 10 | 10908 |
| 11 | 42614 |
| 12 | 153960 |
| 13 | 521235 |
| 14 | 1669720 |
| 15 | 5098938 |
| 16 | 14931060 |
| 17 | 42124236 |
| 18 | 114944700 |
| 19 | 304344780 |
| 20 | 784057428 |
| 21 | 1969912725 |
| 22 | 4836549432 |
| 23 | 11624458120 |
| 24 | 27391979940 |
| 25 | 63368714904 |
| 26 | 144094899520 |
| 27 | 322411353540 |
[1,12,90,520,2535,10908,42614,153960,521235, 1669720,5098938,14931060,42124236,114944700, 304344780,784057428,1969912725,4836549432, 11624458120,27391979940,63368714904,144094899520, 322411353540] |