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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 7 |
| 3 | 16 |
| 4 | 43 |
| 5 | 138 |
| 6 | 527 |
| 7 | 2346 |
| 8 | 11943 |
| 9 | 68418 |
| 10 | 435547 |
| 11 | 3050026 |
| 12 | 23300443 |
| 13 | 192835698 |
| 14 | 1718682167 |
| 15 | 16412205306 |
| 16 | 167173350543 |
| 17 | 1809239622978 |
| 18 | 20732358910387 |
| 19 | 250773962554186 |
| 20 | 3192953259262243 |
| 21 | 42686640718266258 |
| 22 | 597853508941160207 |
[1,3,7,16,43,138,527,2346,11943,68418,435547, 3050026,23300443,192835698,1718682167,16412205306, 167173350543,1809239622978,20732358910387, 250773962554186,3192953259262243, 42686640718266258,597853508941160207] |