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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 4 |
| 4 | 47 |
| 5 | 244 |
| 6 | 1186 |
| 7 | 1384 |
| 8 | 25147 |
| 9 | 112028 |
| 10 | 98374 |
| 11 | 1067720 |
| 12 | 1531401 |
| 13 | 39249768 |
| 14 | 166656772 |
| 15 | 88008656 |
| 16 | 2961699667 |
| 17 | 12412521388 |
| 18 | 51854046982 |
| 19 | 108006842264 |
| 20 | 448816369361 |
| 21 | 3721813363288 |
| 22 | 15401045060572 |
| 23 | 15904199160592 |
| 24 | 131178778841711 |
| 25 | 1080387930269464 |
| 26 | 4443100381114156 |
| 27 | 9124976352166288 |
[0,0,1,4,47,244,1186,1384,25147,112028,98374, 1067720,1531401,39249768,166656772,88008656, 2961699667,12412521388,51854046982,108006842264, 448816369361,3721813363288,15401045060572, 15904199160592,131178778841711,1080387930269464, 4443100381114156,9124976352166288] |