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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 12 |
| 3 | 64 |
| 4 | 429 |
| 5 | 3459 |
| 6 | 32578 |
| 7 | 350928 |
| 8 | 4254819 |
| 9 | 57339343 |
| 10 | 850210608 |
| 11 | 13755324192 |
| 12 | 241123857361 |
| 13 | 4552433489355 |
| 14 | 92097902228022 |
| 15 | 1987543508858416 |
| 16 | 45576279808372215 |
| 17 | 1106640757105043895 |
| 18 | 28364428977533987380 |
| 19 | 765303225207132783360 |
| 20 | 21681823874743612308981 |
[1,3,12,64,429,3459,32578,350928,4254819,57339343, 850210608,13755324192,241123857361,4552433489355, 92097902228022,1987543508858416,45576279808372215, 1106640757105043895,28364428977533987380, 765303225207132783360,21681823874743612308981] |