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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 17 |
| 3 | 82 |
| 4 | 469 |
| 5 | 3176 |
| 6 | 24829 |
| 7 | 219262 |
| 8 | 2157257 |
| 9 | 23405644 |
| 10 | 277601161 |
| 11 | 3572553194 |
| 12 | 49576701277 |
| 13 | 737902011952 |
| 14 | 11725479449909 |
| 15 | 198112664861206 |
| 16 | 3546412902136849 |
| 17 | 67047080265355412 |
| 18 | 1334894917247980417 |
| 19 | 27917550541234128514 |
| 20 | 611874855066753173861 |
| 21 | 14024463626236493578744 |
[1,4,17,82,469,3176,24829,219262,2157257,23405644, 277601161,3572553194,49576701277,737902011952, 11725479449909,198112664861206,3546412902136849, 67047080265355412,1334894917247980417, 27917550541234128514,611874855066753173861, 14024463626236493578744] |