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| n | a(n) |
|---|---|
| 1 | 512 |
| 2 | 2540 |
| 3 | 9560 |
| 4 | 35272 |
| 5 | 123448 |
| 6 | 404672 |
| 7 | 1267488 |
| 8 | 3838248 |
| 9 | 11314584 |
| 10 | 32633748 |
| 11 | 92478904 |
| 12 | 258255040 |
| 13 | 712440672 |
| 14 | 1945445460 |
| 15 | 5266796600 |
| 16 | 14154242168 |
| 17 | 37800414832 |
| 18 | 100406141124 |
| 19 | 265461537608 |
| 20 | 699029097480 |
| 21 | 1834306085296 |
[512,2540,9560,35272,123448,404672,1267488, 3838248,11314584,32633748,92478904,258255040, 712440672,1945445460,5266796600,14154242168, 37800414832,100406141124,265461537608, 699029097480,1834306085296] |