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A081140 as a simple table
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 30 |
| 4 | 600 |
| 5 | 10000 |
| 6 | 150000 |
| 7 | 2100000 |
| 8 | 28000000 |
| 9 | 360000000 |
| 10 | 4500000000 |
| 11 | 55000000000 |
| 12 | 660000000000 |
| 13 | 7800000000000 |
| 14 | 91000000000000 |
| 15 | 1050000000000000 |
| 16 | 12000000000000000 |
| 17 | 136000000000000000 |
| 18 | 1530000000000000000 |
[0,0,1,30,600,10000,150000,2100000,28000000, 360000000,4500000000,55000000000,660000000000, 7800000000000,91000000000000,1050000000000000, 12000000000000000,136000000000000000, 1530000000000000000] |