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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 8 |
| 5 | 47 |
| 6 | 258 |
| 7 | 1426 |
| 8 | 8154 |
| 9 | 48715 |
| 10 | 305012 |
| 11 | 2001719 |
| 12 | 13754692 |
| 13 | 98801976 |
| 14 | 740584196 |
| 15 | 5782218745 |
| 16 | 46942426080 |
| 17 | 395607218279 |
| 18 | 3455493024350 |
| 19 | 31236784338746 |
| 20 | 291836182128670 |
| 21 | 2814329123555051 |
| 22 | 27980637362452980 |
[0,0,0,1,8,47,258,1426,8154,48715,305012,2001719, 13754692,98801976,740584196,5782218745, 46942426080,395607218279,3455493024350, 31236784338746,291836182128670,2814329123555051, 27980637362452980] |