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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 8 |
| 3 | 20 |
| 4 | 114 |
| 5 | 288 |
| 6 | 1156 |
| 7 | 3256 |
| 8 | 23464 |
| 9 | 59716 |
| 10 | 243212 |
| 11 | 699216 |
| 12 | 3659988 |
| 13 | 10265800 |
| 14 | 42353168 |
| 15 | 128163440 |
| 16 | 1127515970 |
| 17 | 2858004752 |
| 18 | 11768578868 |
| 19 | 34294832344 |
| 20 | 180335471424 |
| 21 | 513911386232 |
| 22 | 2137413847256 |
| 23 | 6572758142016 |
| 24 | 41948816796852 |
[1,2,8,20,114,288,1156,3256,23464,59716,243212, 699216,3659988,10265800,42353168,128163440, 1127515970,2858004752,11768578868,34294832344, 180335471424,513911386232,2137413847256, 6572758142016,41948816796852] |