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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 11 |
| 4 | 62 |
| 5 | 442 |
| 6 | 3892 |
| 7 | 40504 |
| 8 | 487496 |
| 9 | 6655688 |
| 10 | 101656592 |
| 11 | 1717234432 |
| 12 | 31789038304 |
| 13 | 639932442976 |
| 14 | 13918144177088 |
| 15 | 325239867277952 |
| 16 | 8126648153635712 |
| 17 | 216210586758515584 |
| 18 | 6102238859442194176 |
| 19 | 182102977877507458048 |
| 20 | 5729025247479379569152 |
[1,1,3,11,62,442,3892,40504,487496,6655688, 101656592,1717234432,31789038304,639932442976, 13918144177088,325239867277952,8126648153635712, 216210586758515584,6102238859442194176, 182102977877507458048,5729025247479379569152] |