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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | 7 |
| 4 | 16 |
| 5 | 73 |
| 6 | 256 |
| 7 | 975 |
| 8 | 3616 |
| 9 | 13521 |
| 10 | 50432 |
| 11 | 188247 |
| 12 | 702512 |
| 13 | 2621849 |
| 14 | 9784832 |
| 15 | 36517535 |
| 16 | 136285248 |
| 17 | 508623521 |
| 18 | 1898208768 |
| 19 | 7084211623 |
| 20 | 26438637648 |
| 21 | 98670339049 |
| 22 | 368242718464 |
| 23 | 1374300534895 |
| 24 | 5128959421024 |
| 25 | 19141537149297 |
| 26 | 71437189176064 |
[1,0,7,16,73,256,975,3616,13521,50432,188247, 702512,2621849,9784832,36517535,136285248, 508623521,1898208768,7084211623,26438637648, 98670339049,368242718464,1374300534895, 5128959421024,19141537149297,71437189176064] |