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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 5 |
| 5 | 28 |
| 6 | 145 |
| 7 | 703 |
| 8 | 3288 |
| 9 | 14980 |
| 10 | 66958 |
| 11 | 294864 |
| 12 | 1283142 |
| 13 | 5529698 |
| 14 | 23637592 |
| 15 | 100350059 |
| 16 | 423511851 |
| 17 | 1778210188 |
| 18 | 7432635711 |
| 19 | 30943479193 |
| 20 | 128365649488 |
| 21 | 530810149910 |
| 22 | 2188638842860 |
| 23 | 9000532494016 |
| 24 | 36925016172060 |
| 25 | 151153394192532 |
[0,0,1,5,28,145,703,3288,14980,66958,294864, 1283142,5529698,23637592,100350059,423511851, 1778210188,7432635711,30943479193,128365649488, 530810149910,2188638842860,9000532494016, 36925016172060,151153394192532] |