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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 2 |
| 2 | 12 |
| 3 | 358 |
| 4 | 19352 |
| 5 | 1709194 |
| 6 | 222722596 |
| 7 | 40122780142 |
| 8 | 9543330683696 |
| 9 | 2895895566420498 |
| 10 | 1091590070839432764 |
| 11 | 500335689476146083190 |
| 12 | 274027979513688992336584 |
| 13 | 176734166480671985581245594 |
[0,2,12,358,19352,1709194,222722596,40122780142, 9543330683696,2895895566420498, 1091590070839432764,500335689476146083190, 274027979513688992336584, 176734166480671985581245594] |