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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 21 |
| 6 | 560 |
| 7 | 6425 |
| 8 | 47385 |
| 9 | 262382 |
| 10 | 1180469 |
| 11 | 4530030 |
| 12 | 15317274 |
| 13 | 46696163 |
| 14 | 130554918 |
| 15 | 339126948 |
| 16 | 826821895 |
| 17 | 1907572610 |
| 18 | 4192279515 |
| 19 | 8824669582 |
| 20 | 17873749440 |
| 21 | 34969097933 |
| 22 | 66304228516 |
| 23 | 122186400487 |
| 24 | 219382723103 |
[0,0,0,0,21,560,6425,47385,262382,1180469,4530030, 15317274,46696163,130554918,339126948,826821895, 1907572610,4192279515,8824669582,17873749440, 34969097933,66304228516,122186400487,219382723103] |