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| n | a(n) |
|---|---|
| 2 | 18 |
| 3 | 102 |
| 4 | 418 |
| 5 | 2006 |
| 6 | 8946 |
| 7 | 41222 |
| 8 | 187202 |
| 9 | 855606 |
| 10 | 3899538 |
| 11 | 17794662 |
| 12 | 81157858 |
| 13 | 370232726 |
| 14 | 1688782386 |
| 15 | 7703577542 |
| 16 | 35140060802 |
| 17 | 160293673206 |
| 18 | 731187195858 |
[18,102,418,2006,8946,41222,187202,855606,3899538, 17794662,81157858,370232726,1688782386,7703577542, 35140060802,160293673206,731187195858] |