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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 8 |
| 3 | 20 |
| 4 | 98 |
| 5 | 293 |
| 6 | 1128 |
| 7 | 3409 |
| 8 | 10846 |
| 9 | 30480 |
| 10 | 84652 |
| 11 | 217677 |
| 12 | 544312 |
| 13 | 1289225 |
| 14 | 2961626 |
| 15 | 6528284 |
| 16 | 13980717 |
| 17 | 28963980 |
| 18 | 58464510 |
| 19 | 114806429 |
| 20 | 220298632 |
| 21 | 412950779 |
| 22 | 758418342 |
| 23 | 1365044296 |
| 24 | 2412766496 |
| 25 | 4189995629 |
| 26 | 7159916414 |
[1,1,8,20,98,293,1128,3409,10846,30480,84652, 217677,544312,1289225,2961626,6528284,13980717, 28963980,58464510,114806429,220298632,412950779, 758418342,1365044296,2412766496,4189995629, 7159916414] |