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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 17 |
| 4 | 133 |
| 5 | 1386 |
| 6 | 18097 |
| 7 | 284299 |
| 8 | 5225985 |
| 9 | 110097836 |
| 10 | 2616190831 |
| 11 | 69236871309 |
| 12 | 2019833025157 |
| 13 | 64403044165942 |
| 14 | 2228441614038837 |
| 15 | 83166830262851591 |
| 16 | 3330183199746011713 |
| 17 | 142418071427679810936 |
| 18 | 6478769455582913796475 |
[1,1,3,17,133,1386,18097,284299,5225985,110097836, 2616190831,69236871309,2019833025157, 64403044165942,2228441614038837,83166830262851591, 3330183199746011713,142418071427679810936, 6478769455582913796475] |