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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 20 |
| 3 | 237 |
| 4 | 4276 |
| 5 | 107225 |
| 6 | 3518526 |
| 7 | 145005721 |
| 8 | 7285611096 |
| 9 | 436297841649 |
| 10 | 30590014543930 |
| 11 | 2474931380486081 |
| 12 | 228308751882636756 |
| 13 | 23772216923031342649 |
| 14 | 2769853988736186166374 |
| 15 | 358463639909150646730665 |
| 16 | 51192480930691715108562736 |
| 17 | 8021370202848006225125239649 |
[1,3,20,237,4276,107225,3518526,145005721, 7285611096,436297841649,30590014543930, 2474931380486081,228308751882636756, 23772216923031342649,2769853988736186166374, 358463639909150646730665, 51192480930691715108562736, 8021370202848006225125239649] |