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| n | a(n) |
|---|---|
| 0 | 7 |
| 1 | 55 |
| 2 | 391 |
| 3 | 2743 |
| 4 | 19207 |
| 5 | 134455 |
| 6 | 941191 |
| 7 | 6588343 |
| 8 | 46118407 |
| 9 | 322828855 |
| 10 | 2259801991 |
| 11 | 15818613943 |
| 12 | 110730297607 |
| 13 | 775112083255 |
| 14 | 5425784582791 |
| 15 | 37980492079543 |
| 16 | 265863444556807 |
| 17 | 1861044111897655 |
| 18 | 13027308783283591 |
| 19 | 91191161482985143 |
[7,55,391,2743,19207,134455,941191,6588343, 46118407,322828855,2259801991,15818613943, 110730297607,775112083255,5425784582791, 37980492079543,265863444556807,1861044111897655, 13027308783283591,91191161482985143] |