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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 9 |
| 2 | 73 |
| 3 | 592 |
| 4 | 4801 |
| 5 | 38935 |
| 6 | 315754 |
| 7 | 2560693 |
| 8 | 20766637 |
| 9 | 168412696 |
| 10 | 1365788605 |
| 11 | 11076234500 |
| 12 | 89825738954 |
| 13 | 728466283251 |
| 14 | 5907695633935 |
| 15 | 47910065991605 |
| 16 | 388539722685585 |
| 17 | 3150968653039294 |
| 18 | 25553638078006016 |
| 19 | 207234184444162395 |
| 20 | 1680622033979603605 |
[1,9,73,592,4801,38935,315754,2560693,20766637, 168412696,1365788605,11076234500,89825738954, 728466283251,5907695633935,47910065991605, 388539722685585,3150968653039294, 25553638078006016,207234184444162395, 1680622033979603605] |