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| n | a(n) |
|---|---|
| 1 | 90 |
| 2 | 180 |
| 3 | 810 |
| 4 | 1470 |
| 5 | 3240 |
| 6 | 18900 |
| 7 | 21000 |
| 8 | 67200 |
| 9 | 268800 |
| 10 | 6561000 |
| 11 | 21609000 |
| 12 | 36750000 |
| 13 | 243855360 |
| 14 | 252000000 |
| 15 | 321489000 |
| 16 | 463050000 |
| 17 | 756315000 |
| 18 | 1913625000 |
| 19 | 136559001600 |
| 20 | 290424960000 |
| 21 | 5664669696000 |
| 22 | 182967724800000 |
| 23 | 257698037760000 |
| 24 | 1054333217387520 |
| 25 | 1138465843200000 |
[90,180,810,1470,3240,18900,21000,67200,268800, 6561000,21609000,36750000,243855360,252000000, 321489000,463050000,756315000,1913625000, 136559001600,290424960000,5664669696000, 182967724800000,257698037760000,1054333217387520, 1138465843200000] |