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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 40 |
| 3 | 1876 |
| 4 | 95072 |
| 5 | 5045474 |
| 6 | 276107408 |
| 7 | 15444602248 |
| 8 | 878268335296 |
| 9 | 50588345910799 |
| 10 | 2944021398570264 |
| 11 | 172780225616034252 |
| 12 | 10211876493716693664 |
| 13 | 607169816926036666486 |
| 14 | 36286222314596227018672 |
| 15 | 2178246170438379512947864 |
| 16 | 131270483744089714062036032 |
[0,1,40,1876,95072,5045474,276107408,15444602248, 878268335296,50588345910799,2944021398570264, 172780225616034252,10211876493716693664, 607169816926036666486,36286222314596227018672, 2178246170438379512947864, 131270483744089714062036032] |