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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 9 |
| 5 | 24 |
| 6 | 76 |
| 7 | 279 |
| 8 | 1156 |
| 9 | 5296 |
| 10 | 26443 |
| 11 | 142418 |
| 12 | 820988 |
| 13 | 5034585 |
| 14 | 32679022 |
| 15 | 223578344 |
| 16 | 1606536889 |
| 17 | 12086679036 |
| 18 | 94951548840 |
| 19 | 777028354999 |
| 20 | 6609770560056 |
| 21 | 58333928795428 |
| 22 | 533203744952179 |
| 23 | 5039919483399502 |
| 24 | 49191925338483848 |
| 25 | 495150794633289137 |
[0,1,2,4,9,24,76,279,1156,5296,26443,142418, 820988,5034585,32679022,223578344,1606536889, 12086679036,94951548840,777028354999, 6609770560056,58333928795428,533203744952179, 5039919483399502,49191925338483848, 495150794633289137] |