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| n | a(n) |
|---|---|
| 0 | 7 |
| 1 | 55 |
| 2 | 487 |
| 3 | 4375 |
| 4 | 39367 |
| 5 | 354295 |
| 6 | 3188647 |
| 7 | 28697815 |
| 8 | 258280327 |
| 9 | 2324522935 |
| 10 | 20920706407 |
| 11 | 188286357655 |
| 12 | 1694577218887 |
| 13 | 15251194969975 |
| 14 | 137260754729767 |
| 15 | 1235346792567895 |
| 16 | 11118121133111047 |
| 17 | 100063090197999415 |
| 18 | 900567811781994727 |
[7,55,487,4375,39367,354295,3188647,28697815, 258280327,2324522935,20920706407,188286357655, 1694577218887,15251194969975,137260754729767, 1235346792567895,11118121133111047, 100063090197999415,900567811781994727] |