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| n | a(n) |
|---|---|
| 1 | 81 |
| 2 | 474 |
| 3 | 2797 |
| 4 | 16360 |
| 5 | 95961 |
| 6 | 562284 |
| 7 | 3296708 |
| 8 | 19317952 |
| 9 | 113216324 |
| 10 | 663531280 |
| 11 | 3889040836 |
| 12 | 22792434328 |
| 13 | 133579200184 |
| 14 | 782877551360 |
| 15 | 4588334140336 |
| 16 | 26891207676512 |
| 17 | 157602635364752 |
| 18 | 923673599517440 |
| 19 | 5413465738496512 |
[81,474,2797,16360,95961,562284,3296708,19317952, 113216324,663531280,3889040836,22792434328, 133579200184,782877551360,4588334140336, 26891207676512,157602635364752,923673599517440, 5413465738496512] |