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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 8 |
| 4 | 174 |
| 5 | 2084 |
| 6 | 21025 |
| 7 | 194064 |
| 8 | 1694224 |
| 9 | 14232672 |
| 10 | 116228871 |
| 11 | 928763000 |
| 12 | 7294771770 |
| 13 | 56497996620 |
| 14 | 432520209420 |
| 15 | 3278863236544 |
| 16 | 24649138276800 |
| 17 | 183964353480832 |
| 18 | 1364323157872947 |
| 19 | 10061883449658936 |
| 20 | 73839952091271730 |
| 21 | 539488089621673500 |
[0,0,0,8,174,2084,21025,194064,1694224,14232672, 116228871,928763000,7294771770,56497996620, 432520209420,3278863236544,24649138276800, 183964353480832,1364323157872947, 10061883449658936,73839952091271730, 539488089621673500] |