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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 10 |
| 5 | 26 |
| 6 | 76 |
| 7 | 232 |
| 8 | 764 |
| 9 | 2620 |
| 10 | 9495 |
| 11 | 35685 |
| 12 | 140031 |
| 13 | 567503 |
| 14 | 2382394 |
| 15 | 10290308 |
| 16 | 45780063 |
| 17 | 208852719 |
| 18 | 977152266 |
| 19 | 4674398032 |
| 20 | 22854255698 |
| 21 | 113957313538 |
| 22 | 579157509082 |
| 23 | 2995214721530 |
| 24 | 15752586526189 |
| 25 | 84145056172981 |
| 26 | 456221504976506 |
| 27 | 2508227921637772 |
[1,1,2,4,10,26,76,232,764,2620,9495,35685,140031, 567503,2382394,10290308,45780063,208852719, 977152266,4674398032,22854255698,113957313538, 579157509082,2995214721530,15752586526189, 84145056172981,456221504976506,2508227921637772] |