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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 21 |
| 3 | 200 |
| 4 | 1950 |
| 5 | 19005 |
| 6 | 185164 |
| 7 | 1803949 |
| 8 | 17574675 |
| 9 | 171218008 |
| 10 | 1668058947 |
| 11 | 16250746331 |
| 12 | 158319795778 |
| 13 | 1542400400537 |
| 14 | 15026541578483 |
| 15 | 146393213915408 |
| 16 | 1426207951308175 |
| 17 | 13894558811577567 |
| 18 | 135365087812821450 |
[1,21,200,1950,19005,185164,1803949,17574675, 171218008,1668058947,16250746331,158319795778, 1542400400537,15026541578483,146393213915408, 1426207951308175,13894558811577567, 135365087812821450] |