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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 26 |
| 4 | 103 |
| 5 | 432 |
| 6 | 1858 |
| 7 | 8189 |
| 8 | 36689 |
| 9 | 166642 |
| 10 | 765147 |
| 11 | 3543811 |
| 12 | 16535520 |
| 13 | 77630619 |
| 14 | 366395694 |
| 15 | 1737136637 |
| 16 | 8268646493 |
| 17 | 39494682800 |
| 18 | 189220899321 |
| 19 | 909028224403 |
| 20 | 4377606117144 |
| 21 | 21127109933769 |
| 22 | 102163191694267 |
| 23 | 494902293671261 |
| 24 | 2401292042004619 |
| 25 | 11668357622150545 |
| 26 | 56775333500447576 |
| 27 | 276596733938294932 |
[1,2,7,26,103,432,1858,8189,36689,166642,765147, 3543811,16535520,77630619,366395694,1737136637, 8268646493,39494682800,189220899321,909028224403, 4377606117144,21127109933769,102163191694267, 494902293671261,2401292042004619, 11668357622150545,56775333500447576, 276596733938294932] |