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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 26082 |
| 3 | 1200864 |
| 4 | 18563580 |
| 5 | 154224000 |
| 6 | 873431160 |
| 7 | 3770958240 |
| 8 | 13432444326 |
| 9 | 41046452160 |
| 10 | 111904857288 |
| 11 | 276175539360 |
| 12 | 632479728468 |
| 13 | 1350390968640 |
| 14 | 2735388749880 |
| 15 | 5258284904544 |
| 16 | 9727162297020 |
| 17 | 17267081573952 |
| 18 | 29779234653770 |
[1,0,26082,1200864,18563580,154224000,873431160, 3770958240,13432444326,41046452160,111904857288, 276175539360,632479728468,1350390968640, 2735388749880,5258284904544,9727162297020, 17267081573952,29779234653770] |