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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 20 |
| 4 | 206 |
| 5 | 2884 |
| 6 | 51222 |
| 7 | 1104970 |
| 8 | 28092136 |
| 9 | 823228920 |
| 10 | 27337210010 |
| 11 | 1014889977694 |
| 12 | 41663456547924 |
| 13 | 1874254936175764 |
| 14 | 91693069544415094 |
| 15 | 4846976442380146890 |
| 16 | 275307423965422835888 |
| 17 | 16721766342325378632688 |
| 18 | 1081506161649434021320626 |
| 19 | 74206134445040935320645046 |
[1,3,20,206,2884,51222,1104970,28092136,823228920, 27337210010,1014889977694,41663456547924, 1874254936175764,91693069544415094, 4846976442380146890,275307423965422835888, 16721766342325378632688,1081506161649434021320626, 74206134445040935320645046] |