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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 8 |
| 2 | 70 |
| 3 | 680 |
| 4 | 7030 |
| 5 | 75296 |
| 6 | 824188 |
| 7 | 9154160 |
| 8 | 102748390 |
| 9 | 1162484240 |
| 10 | 13234625524 |
| 11 | 151434413552 |
| 12 | 1739968195900 |
| 13 | 20061852185600 |
| 14 | 232000158556600 |
| 15 | 2689767185663840 |
| 16 | 31254074218228870 |
| 17 | 363870436065071600 |
| 18 | 4243634227797304900 |
| 19 | 49567706611284604400 |
| 20 | 579776539644142145620 |
[1,8,70,680,7030,75296,824188,9154160,102748390, 1162484240,13234625524,151434413552,1739968195900, 20061852185600,232000158556600,2689767185663840, 31254074218228870,363870436065071600, 4243634227797304900,49567706611284604400, 579776539644142145620] |