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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 272 |
| 4 | 2960 |
| 5 | 21680 |
| 6 | 85584 |
| 7 | 330032 |
| 8 | 916832 |
| 9 | 2402544 |
| 10 | 5543936 |
| 11 | 12188000 |
| 12 | 23612496 |
| 13 | 46235520 |
| 14 | 82329552 |
| 15 | 142808864 |
| 16 | 239006304 |
| 17 | 393144576 |
| 18 | 612427040 |
| 19 | 953341296 |
| 20 | 1420731120 |
| 21 | 2107948720 |
| 22 | 3060955376 |
| 23 | 4384446800 |
| 24 | 6098267968 |
[0,0,272,2960,21680,85584,330032,916832,2402544, 5543936,12188000,23612496,46235520,82329552, 142808864,239006304,393144576,612427040,953341296, 1420731120,2107948720,3060955376,4384446800, 6098267968] |