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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 12 |
| 3 | 108 |
| 4 | 1192 |
| 5 | 14848 |
| 6 | 200432 |
| 7 | 2866752 |
| 8 | 42853392 |
| 9 | 663565616 |
| 10 | 10579117744 |
| 11 | 172911177584 |
| 12 | 2888445810864 |
| 13 | 49203276384624 |
| 14 | 853289008064304 |
| 15 | 15047071017842928 |
| 16 | 269585532569464752 |
| 17 | 4904425594952671344 |
| 18 | 90570287337341726256 |
| 19 | 1697589267552262891760 |
| 20 | 32295562088556275945136 |
[1,2,12,108,1192,14848,200432,2866752,42853392, 663565616,10579117744,172911177584,2888445810864, 49203276384624,853289008064304,15047071017842928, 269585532569464752,4904425594952671344, 90570287337341726256,1697589267552262891760, 32295562088556275945136] |