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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 6160 |
| 5 | 27104 |
| 6 | 157080 |
| 7 | 633600 |
| 8 | 2152920 |
| 9 | 6049120 |
| 10 | 15601432 |
| 11 | 37243360 |
| 12 | 81265800 |
| 13 | 166554080 |
| 14 | 325036800 |
| 15 | 603357216 |
| 16 | 1082004000 |
| 17 | 1863350720 |
| 18 | 3121660080 |
| 19 | 5069606080 |
| 20 | 8058310568 |
| 21 | 12471782400 |
| 22 | 19002534320 |
| 23 | 28292374880 |
| 24 | 41585775000 |
| 25 | 59922289504 |
| 26 | 85450069320 |
[1,0,0,0,6160,27104,157080,633600,2152920,6049120, 15601432,37243360,81265800,166554080,325036800, 603357216,1082004000,1863350720,3121660080, 5069606080,8058310568,12471782400,19002534320, 28292374880,41585775000,59922289504,85450069320] |