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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 8 |
| 4 | 35 |
| 5 | 147 |
| 6 | 654 |
| 7 | 3009 |
| 8 | 14219 |
| 9 | 68605 |
| 10 | 336623 |
| 11 | 1674517 |
| 12 | 8425573 |
| 13 | 42806200 |
| 14 | 219285459 |
| 15 | 1131431170 |
| 16 | 5874504011 |
| 17 | 30670279153 |
| 18 | 160916320637 |
| 19 | 847994498527 |
| 20 | 4486473924741 |
| 21 | 23821682237692 |
| 22 | 126897559943046 |
| 23 | 677992017255423 |
[1,1,2,8,35,147,654,3009,14219,68605,336623, 1674517,8425573,42806200,219285459,1131431170, 5874504011,30670279153,160916320637,847994498527, 4486473924741,23821682237692,126897559943046, 677992017255423] |