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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 216 |
| 5 | 38070 |
| 6 | 1314600 |
| 7 | 21191208 |
| 8 | 207830308 |
| 9 | 1442794332 |
| 10 | 7775083960 |
| 11 | 34530764200 |
| 12 | 131660992164 |
| 13 | 443702617356 |
| 14 | 1350258600008 |
| 15 | 3771242866680 |
| 16 | 9789675562020 |
| 17 | 23856321869260 |
| 18 | 55015308882264 |
| 19 | 120855465245464 |
| 20 | 254284702668580 |
| 21 | 514791197224860 |
| 22 | 1006655249550696 |
[0,0,0,216,38070,1314600,21191208,207830308, 1442794332,7775083960,34530764200,131660992164, 443702617356,1350258600008,3771242866680, 9789675562020,23856321869260,55015308882264, 120855465245464,254284702668580,514791197224860, 1006655249550696] |