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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 2 |
| 2 | 8 |
| 3 | 152 |
| 4 | 6200 |
| 5 | 442552 |
| 6 | 49399320 |
| 7 | 8003532512 |
| 8 | 1784040237288 |
| 9 | 525504809786112 |
| 10 | 198213959637435608 |
| 11 | 93352856625931514024 |
| 12 | 53776417402985961020144 |
| 13 | 37244016639064540041311632 |
[0,2,8,152,6200,442552,49399320,8003532512, 1784040237288,525504809786112,198213959637435608, 93352856625931514024,53776417402985961020144, 37244016639064540041311632] |