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| n | a(n) |
|---|---|
| 3 | 1 |
| 4 | 2 |
| 5 | 4 |
| 6 | 22 |
| 7 | 100 |
| 8 | 421 |
| 9 | 1730 |
| 10 | 7000 |
| 11 | 28056 |
| 12 | 111754 |
| 13 | 443444 |
| 14 | 1755310 |
| 15 | 6937216 |
| 16 | 27389041 |
| 17 | 108067718 |
| 18 | 426244160 |
| 19 | 1680912060 |
| 20 | 6628454969 |
| 21 | 26139689490 |
| 22 | 103095008914 |
| 23 | 406671627876 |
| 24 | 1604475043425 |
| 25 | 6331612489122 |
| 26 | 24991603082792 |
[1,2,4,22,100,421,1730,7000,28056,111754,443444, 1755310,6937216,27389041,108067718,426244160, 1680912060,6628454969,26139689490,103095008914, 406671627876,1604475043425,6331612489122, 24991603082792] |