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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 8 |
| 4 | 236 |
| 5 | 1696 |
| 6 | 32675 |
| 7 | 301384 |
| 8 | 4638576 |
| 9 | 49483138 |
| 10 | 681728204 |
| 11 | 7837276902 |
| 12 | 102283239429 |
| 13 | 1220732524976 |
| 14 | 15513067188008 |
| 15 | 188620289493918 |
| 16 | 2365714170297014 |
| 17 | 29030309635705054 |
| 18 | 361749878496079778 |
| 19 | 4459396682866920534 |
| 20 | 55391169255983979555 |
| 21 | 684363209103066303906 |
[0,1,8,236,1696,32675,301384,4638576,49483138, 681728204,7837276902,102283239429,1220732524976, 15513067188008,188620289493918,2365714170297014, 29030309635705054,361749878496079778, 4459396682866920534,55391169255983979555, 684363209103066303906] |