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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 14 |
| 5 | 44 |
| 6 | 244 |
| 7 | 1196 |
| 8 | 9366 |
| 9 | 62296 |
| 10 | 584016 |
| 11 | 5120548 |
| 12 | 60244028 |
| 13 | 627389924 |
| 14 | 8378159376 |
| 15 | 106097674780 |
| 16 | 1652301306958 |
| 17 | 23655318730276 |
| 18 | 409987534384504 |
| 19 | 6742903763089068 |
| 20 | 130675390985884516 |
| 21 | 2396246933608687036 |
| 22 | 50636625943991790784 |
| 23 | 1032841246318579471748 |
[1,1,2,4,14,44,244,1196,9366,62296,584016,5120548, 60244028,627389924,8378159376,106097674780, 1652301306958,23655318730276,409987534384504, 6742903763089068,130675390985884516, 2396246933608687036,50636625943991790784, 1032841246318579471748] |