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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 7 |
| 3 | 58 |
| 4 | 385 |
| 5 | 2582 |
| 6 | 17740 |
| 7 | 122468 |
| 8 | 846908 |
| 9 | 5858575 |
| 10 | 40519184 |
| 11 | 280214415 |
| 12 | 1937863565 |
| 13 | 13401760093 |
| 14 | 92683431379 |
| 15 | 640976755990 |
| 16 | 4432841883249 |
| 17 | 30656469034888 |
| 18 | 212012773252576 |
| 19 | 1466229429328620 |
| 20 | 10140090725898534 |
[1,7,58,385,2582,17740,122468,846908,5858575, 40519184,280214415,1937863565,13401760093, 92683431379,640976755990,4432841883249, 30656469034888,212012773252576,1466229429328620, 10140090725898534] |