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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 4 |
| 6 | 16 |
| 7 | 121 |
| 8 | 400 |
| 9 | 1600 |
| 10 | 11881 |
| 11 | 39204 |
| 12 | 156816 |
| 13 | 1164241 |
| 14 | 3841600 |
| 15 | 15366400 |
| 16 | 114083761 |
| 17 | 376437604 |
| 18 | 1505750416 |
| 19 | 11179044361 |
| 20 | 36887043600 |
| 21 | 147548174400 |
| 22 | 1095432263641 |
| 23 | 3614553835204 |
| 24 | 14458215340816 |
| 25 | 107341182792481 |
| 26 | 354189388806400 |
| 27 | 1416757555225600 |
[0,0,0,1,4,16,121,400,1600,11881,39204,156816, 1164241,3841600,15366400,114083761,376437604, 1505750416,11179044361,36887043600,147548174400, 1095432263641,3614553835204,14458215340816, 107341182792481,354189388806400,1416757555225600] |