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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 30 |
| 5 | 146 |
| 6 | 814 |
| 7 | 5160 |
| 8 | 36412 |
| 9 | 281188 |
| 10 | 2353296 |
| 11 | 21207308 |
| 12 | 204592912 |
| 13 | 2101390032 |
| 14 | 22870108360 |
| 15 | 262698581176 |
| 16 | 3174062060880 |
| 17 | 40221073046288 |
| 18 | 533111009413024 |
| 19 | 7373468088607152 |
| 20 | 106191106069698976 |
| 21 | 1589392617825708256 |
| 22 | 24679883046981058656 |
| 23 | 396946646811220272704 |
[1,1,2,7,30,146,814,5160,36412,281188,2353296, 21207308,204592912,2101390032,22870108360, 262698581176,3174062060880,40221073046288, 533111009413024,7373468088607152, 106191106069698976,1589392617825708256, 24679883046981058656,396946646811220272704] |