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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 42 |
| 2 | 858 |
| 3 | 15504 |
| 4 | 265650 |
| 5 | 4417686 |
| 6 | 72068304 |
| 7 | 1160068104 |
| 8 | 18490100706 |
| 9 | 292486494300 |
| 10 | 4599035681526 |
| 11 | 71963547329856 |
| 12 | 1121519754006288 |
| 13 | 17419158268943970 |
| 14 | 269767427275060200 |
| 15 | 4167406330765934256 |
[1,42,858,15504,265650,4417686,72068304, 1160068104,18490100706,292486494300,4599035681526, 71963547329856,1121519754006288,17419158268943970, 269767427275060200,4167406330765934256] |