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| n | a(n) |
|---|---|
| 6 | 1 |
| 7 | 0 |
| 8 | 0 |
| 9 | 0 |
| 10 | 0 |
| 11 | 0 |
| 12 | 924 |
| 13 | 3432 |
| 14 | 6006 |
| 15 | 10010 |
| 16 | 16016 |
| 17 | 24752 |
| 18 | 17190264 |
| 19 | 139729800 |
| 20 | 748339320 |
| 21 | 2910015528 |
| 22 | 9794896188 |
| 23 | 30251595066 |
| 24 | 2396910064472 |
| 25 | 33228482071400 |
| 26 | 291616291666700 |
| 27 | 2036218597884900 |
| 28 | 11895959650285620 |
| 29 | 61536913327513260 |
| 30 | 1662981928016982300 |
[1,0,0,0,0,0,924,3432,6006,10010,16016,24752, 17190264,139729800,748339320,2910015528, 9794896188,30251595066,2396910064472, 33228482071400,291616291666700,2036218597884900, 11895959650285620,61536913327513260, 1662981928016982300] |