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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 26 |
| 4 | 744 |
| 5 | 18475 |
| 6 | 326446 |
| 7 | 4292149 |
| 8 | 43506488 |
| 9 | 354466019 |
| 10 | 2391684440 |
| 11 | 13770292256 |
| 12 | 69044240450 |
| 13 | 307750080388 |
| 14 | 1235903232638 |
| 15 | 4537248102720 |
| 16 | 15362780912768 |
| 17 | 48489022864600 |
| 18 | 143504551536641 |
| 19 | 401488209735955 |
[0,0,26,744,18475,326446,4292149,43506488, 354466019,2391684440,13770292256,69044240450, 307750080388,1235903232638,4537248102720, 15362780912768,48489022864600,143504551536641, 401488209735955] |