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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 76 |
| 3 | 3256 |
| 4 | 235408 |
| 5 | 25823744 |
| 6 | 4007103296 |
| 7 | 836059707008 |
| 8 | 225808591264000 |
| 9 | 76659294873275392 |
| 10 | 31954924327960714240 |
| 11 | 16046151385106990553088 |
| 12 | 9553929740491469212061696 |
| 13 | 6655283798759275562178347008 |
[1,4,76,3256,235408,25823744,4007103296, 836059707008,225808591264000,76659294873275392, 31954924327960714240,16046151385106990553088, 9553929740491469212061696, 6655283798759275562178347008] |