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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 9 |
| 4 | 52 |
| 5 | 545 |
| 6 | 6366 |
| 7 | 98707 |
| 8 | 1700840 |
| 9 | 35405505 |
| 10 | 817958170 |
| 11 | 21500633891 |
| 12 | 618661892652 |
| 13 | 19636408658737 |
| 14 | 675144805723766 |
| 15 | 25147073628948195 |
| 16 | 1004734122294047056 |
| 17 | 42965745214637476097 |
| 18 | 1955039747566085781426 |
| 19 | 94404335950307686644163 |
| 20 | 4818562790963397438214100 |
[1,2,9,52,545,6366,98707,1700840,35405505, 817958170,21500633891,618661892652,19636408658737, 675144805723766,25147073628948195, 1004734122294047056,42965745214637476097, 1955039747566085781426,94404335950307686644163, 4818562790963397438214100] |