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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 17 |
| 4 | 151 |
| 5 | 1899 |
| 6 | 31711 |
| 7 | 672697 |
| 8 | 17551323 |
| 9 | 549500451 |
| 10 | 20246665349 |
| 11 | 864261579999 |
| 12 | 42190730051687 |
| 13 | 2329965898878307 |
| 14 | 144220683681814515 |
| 15 | 9926440976428215117 |
| 16 | 754465679498026783923 |
| 17 | 62939664181821196179459 |
| 18 | 5732069150321309755351161 |
| 19 | 567176164248814234096702451 |
[1,1,3,17,151,1899,31711,672697,17551323, 549500451,20246665349,864261579999,42190730051687, 2329965898878307,144220683681814515, 9926440976428215117,754465679498026783923, 62939664181821196179459,5732069150321309755351161, 567176164248814234096702451] |