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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 9 |
| 3 | 39 |
| 4 | 189 |
| 5 | 896 |
| 6 | 4417 |
| 7 | 21576 |
| 8 | 107073 |
| 9 | 529240 |
| 10 | 2634775 |
| 11 | 13093073 |
| 12 | 65293025 |
| 13 | 325328452 |
| 14 | 1623926483 |
| 15 | 8102847121 |
| 16 | 40470054325 |
| 17 | 202092673302 |
| 18 | 1009726970717 |
| 19 | 5044555157671 |
| 20 | 25210265604259 |
| 21 | 125984999325888 |
| 22 | 629709173954791 |
| 23 | 3147443384782430 |
| 24 | 15733446109267457 |
| 25 | 78648558624960914 |
[1,2,9,39,189,896,4417,21576,107073,529240, 2634775,13093073,65293025,325328452,1623926483, 8102847121,40470054325,202092673302,1009726970717, 5044555157671,25210265604259,125984999325888, 629709173954791,3147443384782430, 15733446109267457,78648558624960914] |