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| n | a(n) |
|---|---|
| 1 | 126 |
| 2 | 460 |
| 3 | 1690 |
| 4 | 6225 |
| 5 | 22950 |
| 6 | 84626 |
| 7 | 312019 |
| 8 | 1150208 |
| 9 | 4239225 |
| 10 | 15621426 |
| 11 | 57556155 |
| 12 | 212037241 |
| 13 | 781074572 |
| 14 | 2877011660 |
| 15 | 10596599460 |
| 16 | 39027676220 |
| 17 | 143735627861 |
| 18 | 529352597361 |
| 19 | 1949472483601 |
| 20 | 7179308057596 |
| 21 | 26438877143476 |
| 22 | 97364252272077 |
[126,460,1690,6225,22950,84626,312019,1150208, 4239225,15621426,57556155,212037241,781074572, 2877011660,10596599460,39027676220,143735627861, 529352597361,1949472483601,7179308057596, 26438877143476,97364252272077] |