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| n | a(n) |
|---|---|
| 20 | 12600 |
| 21 | 78120 |
| 22 | 189000 |
| 23 | 549000 |
| 24 | 1389960 |
| 25 | 2858640 |
| 26 | 6471699 |
| 27 | 15289662 |
| 28 | 29639082 |
| 29 | 64025820 |
| 30 | 134997382 |
| 31 | 267550925 |
| 32 | 545274648 |
| 33 | 1161661901 |
| 34 | 2223888268 |
| 35 | 4552401195 |
| 36 | 9185643748 |
| 37 | 17829746962 |
| 38 | 35102264675 |
| 39 | 71613947350 |
| 40 | 135793314152 |
| 41 | 270167493481 |
| 42 | 534784841445 |
[12600,78120,189000,549000,1389960,2858640, 6471699,15289662,29639082,64025820,134997382, 267550925,545274648,1161661901,2223888268, 4552401195,9185643748,17829746962,35102264675, 71613947350,135793314152,270167493481, 534784841445] |