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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 9 |
| 3 | 32 |
| 4 | 130 |
| 5 | 600 |
| 6 | 2816 |
| 7 | 13504 |
| 8 | 65521 |
| 9 | 319835 |
| 10 | 1566612 |
| 11 | 7687400 |
| 12 | 37759082 |
| 13 | 185561978 |
| 14 | 912173296 |
| 15 | 4484666199 |
| 16 | 22050441495 |
| 17 | 108423345160 |
| 18 | 533136119034 |
| 19 | 2621552944596 |
| 20 | 12890861627884 |
| 21 | 63387955860276 |
| 22 | 311696797461453 |
[1,9,32,130,600,2816,13504,65521,319835,1566612, 7687400,37759082,185561978,912173296,4484666199, 22050441495,108423345160,533136119034, 2621552944596,12890861627884,63387955860276, 311696797461453] |