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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 1 |
| 6 | 10 |
| 7 | 80 |
| 8 | 611 |
| 9 | 4602 |
| 10 | 34791 |
| 11 | 265606 |
| 12 | 2054034 |
| 13 | 16094883 |
| 14 | 127693729 |
| 15 | 1024649237 |
| 16 | 8306343347 |
| 17 | 67952829212 |
| 18 | 560471786912 |
| 19 | 4656785469564 |
| 20 | 38948533963500 |
| 21 | 327715193729107 |
| 22 | 2772468576820531 |
[0,0,0,0,1,10,80,611,4602,34791,265606,2054034, 16094883,127693729,1024649237,8306343347, 67952829212,560471786912,4656785469564, 38948533963500,327715193729107,2772468576820531] |