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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 6 |
| 3 | 70 |
| 4 | 870 |
| 5 | 36518 |
| 6 | 1828134 |
| 7 | 300503590 |
| 8 | 60273667110 |
| 9 | 39431461330982 |
| 10 | 31648840352155686 |
| 11 | 82716718794775795750 |
| 12 | 265590372390118027343910 |
| 13 | 2775704953984257023035176998 |
| 14 | 35650312393325457366304103888934 |
| 15 | 1490221075739321877604231759426844710 |
[2,6,70,870,36518,1828134,300503590,60273667110, 39431461330982,31648840352155686, 82716718794775795750,265590372390118027343910, 2775704953984257023035176998, 35650312393325457366304103888934, 1490221075739321877604231759426844710] |