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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 8 |
| 3 | 28 |
| 4 | 218 |
| 5 | 1074 |
| 6 | 7384 |
| 7 | 41228 |
| 8 | 262004 |
| 9 | 1565836 |
| 10 | 9730070 |
| 11 | 59336930 |
| 12 | 368674288 |
[0,8,28,218,1074,7384,41228,262004,1565836, 9730070,59336930,368674288] |