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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 4 |
| 3 | 16 |
| 4 | 324 |
| 5 | 6400 |
| 6 | 23716 |
| 7 | 467856 |
| 8 | 9229444 |
| 9 | 34199104 |
| 10 | 674648676 |
| 11 | 13308852496 |
| 12 | 49315084900 |
| 13 | 972842923584 |
| 14 | 19191356070436 |
| 15 | 71112318227344 |
| 16 | 1402838821160100 |
| 17 | 27673922144716864 |
| 18 | 102543913568745796 |
| 19 | 2022892607269941264 |
[0,4,16,324,6400,23716,467856,9229444,34199104, 674648676,13308852496,49315084900,972842923584, 19191356070436,71112318227344,1402838821160100, 27673922144716864,102543913568745796, 2022892607269941264] |