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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 0 |
| 7 | 0 |
| 8 | 60 |
| 9 | 120 |
| 10 | 960 |
| 11 | 1800 |
| 12 | 9300 |
| 13 | 16800 |
| 14 | 71400 |
| 15 | 126000 |
| 16 | 480060 |
| 17 | 834120 |
| 18 | 2968560 |
| 19 | 5103000 |
| 20 | 17355300 |
| 21 | 29607600 |
| 22 | 97567800 |
| 23 | 165528000 |
| 24 | 533274060 |
| 25 | 901020120 |
| 26 | 2855012160 |
| 27 | 4809004200 |
| 28 | 15050517300 |
| 29 | 25292030400 |
| 30 | 78417448200 |
| 31 | 131542866000 |
| 32 | 404936532060 |
[0,0,0,0,0,0,0,60,120,960,1800,9300,16800,71400, 126000,480060,834120,2968560,5103000,17355300, 29607600,97567800,165528000,533274060,901020120, 2855012160,4809004200,15050517300,25292030400, 78417448200,131542866000,404936532060] |