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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 4 |
| 4 | 94 |
| 5 | 1450 |
| 6 | 20689 |
| 7 | 284702 |
| 8 | 3856027 |
| 9 | 51806212 |
| 10 | 693213401 |
| 11 | 9256626752 |
| 12 | 123474805622 |
| 13 | 1646142914632 |
| 14 | 21939928353674 |
| 15 | 292375085482054 |
| 16 | 3895949812693799 |
| 17 | 51912242778609770 |
| 18 | 691699897071467742 |
[0,0,4,94,1450,20689,284702,3856027,51806212, 693213401,9256626752,123474805622,1646142914632, 21939928353674,292375085482054,3895949812693799, 51912242778609770,691699897071467742] |