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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 0 |
| 7 | 60 |
| 8 | 140 |
| 9 | 518 |
| 10 | 1444 |
| 11 | 8556 |
| 12 | 31992 |
| 13 | 220456 |
| 14 | 984208 |
| 15 | 7453080 |
| 16 | 39692800 |
| 17 | 289981136 |
| 18 | 1467791790 |
| 19 | 14316379108 |
| 20 | 86001855074 |
| 21 | 949804475890 |
| 22 | 6494842788046 |
| 23 | 73636377696714 |
[0,0,0,0,0,0,60,140,518,1444,8556,31992,220456, 984208,7453080,39692800,289981136,1467791790, 14316379108,86001855074,949804475890, 6494842788046,73636377696714] |