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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 378 |
| 3 | 4032 |
| 4 | 24948 |
| 5 | 84672 |
| 6 | 272706 |
| 7 | 689472 |
| 8 | 1471554 |
| 9 | 3003840 |
| 10 | 6041952 |
| 11 | 9640512 |
| 12 | 17409420 |
| 13 | 28304640 |
| 14 | 42284052 |
| 15 | 64338624 |
| 16 | 101413620 |
| 17 | 131362560 |
| 18 | 198388554 |
| 19 | 275679936 |
| 20 | 359236080 |
| 21 | 484706880 |
| 22 | 685716192 |
| 23 | 805569408 |
| 24 | 1113880362 |
| 25 | 1430763264 |
| 26 | 1734830244 |
| 27 | 2189464704 |
[1,0,378,4032,24948,84672,272706,689472,1471554, 3003840,6041952,9640512,17409420,28304640, 42284052,64338624,101413620,131362560,198388554, 275679936,359236080,484706880,685716192,805569408, 1113880362,1430763264,1734830244,2189464704] |