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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 16 |
| 4 | 149 |
| 5 | 1656 |
| 6 | 22567 |
| 7 | 369664 |
| 8 | 7081209 |
| 9 | 155178928 |
| 10 | 3830958251 |
| 11 | 105267080304 |
| 12 | 3187172910517 |
| 13 | 105437661606616 |
| 14 | 3784329536385231 |
| 15 | 146474021771040856 |
| 16 | 6081955388047685873 |
| 17 | 269686446704697314016 |
| 18 | 12719466142269818201299 |
[1,1,3,16,149,1656,22567,369664,7081209,155178928, 3830958251,105267080304,3187172910517, 105437661606616,3784329536385231, 146474021771040856,6081955388047685873, 269686446704697314016,12719466142269818201299] |