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| n | a(n) |
|---|---|
| 1 | 5 |
| 2 | 40 |
| 3 | 305 |
| 4 | 1854 |
| 5 | 10677 |
| 6 | 58852 |
| 7 | 318220 |
| 8 | 1695030 |
| 9 | 8941285 |
| 10 | 46760710 |
| 11 | 242970442 |
| 12 | 1255597078 |
| 13 | 6458360287 |
| 14 | 33085037590 |
| 15 | 168885713050 |
| 16 | 859370947890 |
| 17 | 4360537440625 |
| 18 | 22069557056618 |
| 19 | 111441207638795 |
| 20 | 561547964534696 |
[5,40,305,1854,10677,58852,318220,1695030,8941285, 46760710,242970442,1255597078,6458360287, 33085037590,168885713050,859370947890, 4360537440625,22069557056618,111441207638795, 561547964534696] |