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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 165 |
| 5 | 4135 |
| 6 | 47010 |
| 7 | 337860 |
| 8 | 1790472 |
| 9 | 7622340 |
| 10 | 27489825 |
| 11 | 87018360 |
| 12 | 247874770 |
| 13 | 647091588 |
| 14 | 1569661600 |
| 15 | 3576049620 |
| 16 | 7716906900 |
| 17 | 15881735580 |
| 18 | 31347485274 |
| 19 | 59618165895 |
| 20 | 109678780695 |
| 21 | 195827638105 |
| 22 | 340301983890 |
| 23 | 576974687080 |
[0,0,1,165,4135,47010,337860,1790472,7622340, 27489825,87018360,247874770,647091588,1569661600, 3576049620,7716906900,15881735580,31347485274, 59618165895,109678780695,195827638105, 340301983890,576974687080] |