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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 39 |
| 4 | 321 |
| 5 | 3603 |
| 6 | 51391 |
| 7 | 884873 |
| 8 | 17770445 |
| 9 | 406673247 |
| 10 | 10431884283 |
| 11 | 296262164637 |
| 12 | 9224841015745 |
| 13 | 312441152401067 |
| 14 | 11434829066996087 |
| 15 | 449675059390576257 |
| 16 | 18908960744072894325 |
| 17 | 846638474386244188311 |
| 18 | 40213487658138717885907 |
| 19 | 2019543479160709325145893 |
[1,2,7,39,321,3603,51391,884873,17770445, 406673247,10431884283,296262164637,9224841015745, 312441152401067,11434829066996087, 449675059390576257,18908960744072894325, 846638474386244188311,40213487658138717885907, 2019543479160709325145893] |