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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 12 |
| 4 | 76 |
| 5 | 655 |
| 6 | 6906 |
| 7 | 85204 |
| 8 | 1201824 |
| 9 | 19071693 |
| 10 | 336276370 |
| 11 | 6522231826 |
| 12 | 138001776936 |
| 13 | 3163262495419 |
| 14 | 78085513281426 |
| 15 | 2065232400748560 |
| 16 | 58263438835891456 |
| 17 | 1746434237976248665 |
| 18 | 55428349087686179682 |
[1,3,12,76,655,6906,85204,1201824,19071693, 336276370,6522231826,138001776936,3163262495419, 78085513281426,2065232400748560,58263438835891456, 1746434237976248665,55428349087686179682] |