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| n | a(n) |
|---|---|
| 2 | 9 |
| 3 | 180 |
| 4 | 2070 |
| 5 | 17775 |
| 6 | 125865 |
| 7 | 773766 |
| 8 | 4260645 |
| 9 | 21453975 |
| 10 | 100250100 |
| 11 | 439479198 |
| 12 | 1822654251 |
| 13 | 7198716870 |
| 14 | 27221451885 |
| 15 | 98988000120 |
| 16 | 347428124352 |
| 17 | 1180620288702 |
| 18 | 3894719205510 |
| 19 | 12501561121560 |
| 20 | 39124469772495 |
[9,180,2070,17775,125865,773766,4260645,21453975, 100250100,439479198,1822654251,7198716870, 27221451885,98988000120,347428124352, 1180620288702,3894719205510,12501561121560, 39124469772495] |