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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 6 |
| 5 | 37 |
| 6 | 388 |
| 7 | 6004 |
| 8 | 148759 |
| 9 | 5974184 |
| 10 | 404509191 |
| 11 | 47552739892 |
| 12 | 9923861406343 |
| 13 | 3735194287263442 |
| 14 | 2565376853616300801 |
| 15 | 3244070698095148283628 |
| 16 | 7607050619214875184974489 |
| 17 | 33269229977451262849539412860 |
| 18 | 272689940536978851416633440863567 |
[0,1,1,6,37,388,6004,148759,5974184,404509191, 47552739892,9923861406343,3735194287263442, 2565376853616300801,3244070698095148283628, 7607050619214875184974489, 33269229977451262849539412860, 272689940536978851416633440863567] |