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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 17 |
| 4 | 73 |
| 5 | 321 |
| 6 | 1485 |
| 7 | 7073 |
| 8 | 34513 |
| 9 | 171585 |
| 10 | 866133 |
| 11 | 4427313 |
| 12 | 22870425 |
| 13 | 119208321 |
| 14 | 626178717 |
| 15 | 3311424321 |
| 16 | 17615732385 |
| 17 | 94202293633 |
| 18 | 506116560293 |
| 19 | 2730607756881 |
| 20 | 14788011564009 |
| 21 | 80361643637953 |
| 22 | 438070231780973 |
[1,1,5,17,73,321,1485,7073,34513,171585,866133, 4427313,22870425,119208321,626178717,3311424321, 17615732385,94202293633,506116560293, 2730607756881,14788011564009,80361643637953, 438070231780973] |