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| n | a(n) |
|---|---|
| 1 | 512 |
| 2 | 2696 |
| 3 | 12260 |
| 4 | 47140 |
| 5 | 170504 |
| 6 | 586508 |
| 7 | 1964388 |
| 8 | 6462708 |
| 9 | 21003228 |
| 10 | 67662328 |
| 11 | 216533720 |
| 12 | 689480684 |
| 13 | 2187191068 |
| 14 | 6918332408 |
| 15 | 21836278536 |
| 16 | 68808353156 |
| 17 | 216551437648 |
| 18 | 680873827704 |
| 19 | 2139217784216 |
| 20 | 6717384585616 |
| 21 | 21084279168188 |
[512,2696,12260,47140,170504,586508,1964388, 6462708,21003228,67662328,216533720,689480684, 2187191068,6918332408,21836278536,68808353156, 216551437648,680873827704,2139217784216, 6717384585616,21084279168188] |