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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 0 |
| 5 | 10 |
| 6 | 75 |
| 7 | 126 |
| 8 | 196 |
| 9 | 1548 |
| 10 | 15525 |
| 11 | 39820 |
| 12 | 161106 |
| 13 | 358722 |
| 14 | 3705884 |
| 15 | 46623045 |
| 16 | 142988280 |
| 17 | 768721504 |
| 18 | 3560215293 |
| 19 | 12250746432 |
| 20 | 144581799790 |
| 21 | 2542575063630 |
| 22 | 8955836934660 |
| 23 | 55657973021431 |
| 24 | 319349051391228 |
| 25 | 1983548989621200 |
| 26 | 7898257536096850 |
[0,0,1,3,0,10,75,126,196,1548,15525,39820,161106, 358722,3705884,46623045,142988280,768721504, 3560215293,12250746432,144581799790,2542575063630, 8955836934660,55657973021431,319349051391228, 1983548989621200,7898257536096850] |