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| n | a(n) |
|---|---|
| 1 | 264 |
| 2 | 1128 |
| 3 | 5272 |
| 4 | 24832 |
| 5 | 118248 |
| 6 | 562800 |
| 7 | 2680000 |
| 8 | 12760448 |
| 9 | 60758008 |
| 10 | 289298976 |
| 11 | 1377475600 |
| 12 | 6558823720 |
| 13 | 31229466280 |
| 14 | 148698094888 |
| 15 | 708018868272 |
| 16 | 3371204831376 |
| 17 | 16051843045856 |
| 18 | 76430201410000 |
| 19 | 363919139999024 |
[264,1128,5272,24832,118248,562800,2680000, 12760448,60758008,289298976,1377475600,6558823720, 31229466280,148698094888,708018868272, 3371204831376,16051843045856,76430201410000, 363919139999024] |