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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 31 |
| 4 | 257 |
| 5 | 2551 |
| 6 | 30065 |
| 7 | 407191 |
| 8 | 6214577 |
| 9 | 105530071 |
| 10 | 1972879025 |
| 11 | 40213910551 |
| 12 | 886979957297 |
| 13 | 21044674731991 |
| 14 | 534313527291185 |
| 15 | 14448883517785111 |
| 16 | 414475305054698417 |
| 17 | 12568507978358276311 |
| 18 | 401658204472560090545 |
| 19 | 13490011548122407566871 |
| 20 | 474964861088609044357937 |
| 21 | 17491333169997896126211031 |
[1,1,5,31,257,2551,30065,407191,6214577,105530071, 1972879025,40213910551,886979957297, 21044674731991,534313527291185,14448883517785111, 414475305054698417,12568507978358276311, 401658204472560090545,13490011548122407566871, 474964861088609044357937, 17491333169997896126211031] |