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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 8 |
| 3 | 85 |
| 4 | 988 |
| 5 | 10696 |
| 6 | 104676 |
| 7 | 939863 |
| 8 | 7980376 |
| 9 | 65679175 |
| 10 | 532115106 |
| 11 | 4279710436 |
| 12 | 34311898336 |
| 13 | 274729437763 |
| 14 | 2198561705222 |
| 15 | 17590732383423 |
| 16 | 140732804110800 |
| 17 | 1125884352801489 |
| 18 | 9007145852828686 |
| 19 | 72057404552774828 |
| 20 | 576460059887430848 |
| 21 | 4611683426113781209 |
[1,1,8,85,988,10696,104676,939863,7980376, 65679175,532115106,4279710436,34311898336, 274729437763,2198561705222,17590732383423, 140732804110800,1125884352801489,9007145852828686, 72057404552774828,576460059887430848, 4611683426113781209] |