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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 19 |
| 2 | 209 |
| 3 | 1710 |
| 4 | 11495 |
| 5 | 66862 |
| 6 | 347339 |
| 7 | 1645875 |
| 8 | 7221520 |
| 9 | 29668595 |
| 10 | 115116233 |
| 11 | 424720338 |
| 12 | 1498263563 |
| 13 | 5076482415 |
| 14 | 16583497160 |
| 15 | 52399330389 |
| 16 | 160586833362 |
| 17 | 478482249548 |
| 18 | 1388989067820 |
| 19 | 3935549005725 |
| 20 | 10901608510397 |
| 21 | 29565343541110 |
| 22 | 78604103339462 |
[1,19,209,1710,11495,66862,347339,1645875,7221520, 29668595,115116233,424720338,1498263563, 5076482415,16583497160,52399330389,160586833362, 478482249548,1388989067820,3935549005725, 10901608510397,29565343541110,78604103339462] |