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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 2 |
| 2 | 8 |
| 3 | 606 |
| 4 | 24881 |
| 5 | 903855 |
| 6 | 18345919 |
| 7 | 303176603 |
| 8 | 7423167971 |
| 9 | 247828120179 |
| 10 | 6034957650107 |
| 11 | 7948827377158 |
[0,2,8,606,24881,903855,18345919,303176603, 7423167971,247828120179,6034957650107, 7948827377158] |