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| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 120 |
| 3 | 2530 |
| 4 | 58458 |
| 5 | 1317540 |
| 6 | 30132444 |
| 7 | 684657326 |
| 8 | 15594228288 |
| 9 | 354894362166 |
| 10 | 8078976180614 |
| 11 | 183894888689408 |
| 12 | 4185999926427220 |
| 13 | 95284617951103300 |
| 14 | 2168945067666040200 |
| 15 | 49371181800142293644 |
| 16 | 1123825227937533564738 |
[3,120,2530,58458,1317540,30132444,684657326, 15594228288,354894362166,8078976180614, 183894888689408,4185999926427220, 95284617951103300,2168945067666040200, 49371181800142293644,1123825227937533564738] |