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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 3 |
| 5 | 8 |
| 6 | 28 |
| 7 | 136 |
| 8 | 715 |
| 9 | 3968 |
| 10 | 24928 |
| 11 | 176896 |
| 12 | 1358611 |
| 13 | 11184128 |
| 14 | 99463620 |
| 15 | 951878656 |
| 16 | 9704336283 |
| 17 | 104932671488 |
| 18 | 1202007133768 |
| 19 | 14544442556416 |
| 20 | 185212683647587 |
| 21 | 2475749026562048 |
| 22 | 34672375957634412 |
| 23 | 507711943253426176 |
| 24 | 7757454418668014443 |
| 25 | 123460740095103991808 |
[0,0,0,1,3,8,28,136,715,3968,24928,176896,1358611, 11184128,99463620,951878656,9704336283, 104932671488,1202007133768,14544442556416, 185212683647587,2475749026562048, 34672375957634412,507711943253426176, 7757454418668014443,123460740095103991808] |