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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 6 |
| 3 | 57 |
| 4 | 820 |
| 5 | 16105 |
| 6 | 402234 |
| 7 | 12204241 |
| 8 | 435984840 |
| 9 | 17927094321 |
| 10 | 833994048910 |
| 11 | 43309534450633 |
| 12 | 2483526865641276 |
| 13 | 155867505885345241 |
| 14 | 10627079738421409410 |
| 15 | 782175399728156197665 |
| 16 | 61812037545704964935440 |
| 17 | 5220088150634922700769761 |
| 18 | 469168161404536131943150998 |
[1,6,57,820,16105,402234,12204241,435984840, 17927094321,833994048910,43309534450633, 2483526865641276,155867505885345241, 10627079738421409410,782175399728156197665, 61812037545704964935440,5220088150634922700769761, 469168161404536131943150998] |