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| n | a(n) |
|---|---|
| 0 | 2 |
| 1 | 1 |
| 2 | 3 |
| 3 | 8 |
| 4 | 33 |
| 5 | 164 |
| 6 | 985 |
| 7 | 6894 |
| 8 | 55153 |
| 9 | 496376 |
| 10 | 4963761 |
| 11 | 54601370 |
| 12 | 655216441 |
| 13 | 8517813732 |
| 14 | 119249392249 |
| 15 | 1788740883734 |
| 16 | 28619854139745 |
| 17 | 486537520375664 |
| 18 | 8757675366761953 |
| 19 | 166395831968477106 |
| 20 | 3327916639369542121 |
| 21 | 69886249426760384540 |
| 22 | 1537497487388728459881 |
[2,1,3,8,33,164,985,6894,55153,496376,4963761, 54601370,655216441,8517813732,119249392249, 1788740883734,28619854139745,486537520375664, 8757675366761953,166395831968477106, 3327916639369542121,69886249426760384540, 1537497487388728459881] |