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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 8 |
| 3 | 22 |
| 4 | 68 |
| 5 | 256 |
| 6 | 1232 |
| 7 | 7504 |
| 8 | 55328 |
| 9 | 473536 |
| 10 | 4575872 |
| 11 | 49068544 |
| 12 | 577138688 |
| 13 | 7381298176 |
| 14 | 101940887552 |
| 15 | 1511556143104 |
| 16 | 23945902174208 |
| 17 | 403579232444416 |
| 18 | 7209532170616832 |
| 19 | 136064164750065664 |
| 20 | 2705030337676771328 |
| 21 | 56501002847062982656 |
| 22 | 1237002733471733645312 |
[1,3,8,22,68,256,1232,7504,55328,473536,4575872, 49068544,577138688,7381298176,101940887552, 1511556143104,23945902174208,403579232444416, 7209532170616832,136064164750065664, 2705030337676771328,56501002847062982656, 1237002733471733645312] |