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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 10 |
| 3 | 105 |
| 4 | 1176 |
| 5 | 13860 |
| 6 | 169884 |
| 7 | 2147145 |
| 8 | 27810640 |
| 9 | 367479684 |
| 10 | 4936848280 |
| 11 | 67255063876 |
| 12 | 927192688800 |
| 13 | 12914469594000 |
| 14 | 181497968832600 |
| 15 | 2570903476583625 |
| 16 | 36671501616314400 |
| 17 | 526348636137670500 |
| 18 | 7597019633665077000 |
| 19 | 110205019733436728100 |
[0,1,10,105,1176,13860,169884,2147145,27810640, 367479684,4936848280,67255063876,927192688800, 12914469594000,181497968832600,2570903476583625, 36671501616314400,526348636137670500, 7597019633665077000,110205019733436728100] |