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| n | a(n) |
|---|---|
| 1 | 18 |
| 2 | 86 |
| 3 | 680 |
| 4 | 835 |
| 5 | 7087 |
| 6 | 12788 |
| 7 | 18478 |
| 8 | 128117 |
| 9 | 385732 |
| 10 | 2206280 |
| 11 | 13176873 |
| 12 | 33185141 |
| 13 | 68388408 |
| 14 | 335213686 |
| 15 | 1365888758 |
| 16 | 4771043885 |
| 17 | 24740884085 |
[18,86,680,835,7087,12788,18478,128117,385732, 2206280,13176873,33185141,68388408,335213686, 1365888758,4771043885,24740884085] |