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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 7 |
| 3 | 28 |
| 4 | 74 |
| 5 | 440 |
| 6 | 2514 |
| 7 | 12601 |
| 8 | 71009 |
| 9 | 401521 |
| 10 | 2216357 |
| 11 | 12389835 |
| 12 | 69428069 |
| 13 | 387643511 |
| 14 | 2166781692 |
| 15 | 12118679269 |
| 16 | 67747174495 |
| 17 | 378749710935 |
| 18 | 2117679034553 |
| 19 | 11839819553660 |
| 20 | 66195424589209 |
| 21 | 370099033893829 |
| 22 | 2069216112387034 |
[1,7,28,74,440,2514,12601,71009,401521,2216357, 12389835,69428069,387643511,2166781692, 12118679269,67747174495,378749710935, 2117679034553,11839819553660,66195424589209, 370099033893829,2069216112387034] |