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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 21 |
| 3 | 472 |
| 4 | 16581 |
| 5 | 795736 |
| 6 | 48509641 |
| 7 | 3589729760 |
| 8 | 312603962985 |
| 9 | 31321633489408 |
| 10 | 3549706188092541 |
| 11 | 448973808123051520 |
| 12 | 62697159481460439469 |
| 13 | 9581292408000225087488 |
| 14 | 1590488540940006100524657 |
| 15 | 284993765391981838318575616 |
| 16 | 54826610288277007690469896017 |
[1,2,21,472,16581,795736,48509641,3589729760, 312603962985,31321633489408,3549706188092541, 448973808123051520,62697159481460439469, 9581292408000225087488,1590488540940006100524657, 284993765391981838318575616, 54826610288277007690469896017] |