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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 23 |
| 5 | 99 |
| 6 | 452 |
| 7 | 2136 |
| 8 | 10313 |
| 9 | 50469 |
| 10 | 249062 |
| 11 | 1235466 |
| 12 | 6147803 |
| 13 | 30650439 |
| 14 | 152986472 |
| 15 | 764135196 |
| 16 | 3818284493 |
| 17 | 19084248009 |
| 18 | 95399716682 |
| 19 | 476934013326 |
| 20 | 2384476356383 |
| 21 | 11921800651179 |
| 22 | 59607259863692 |
| 23 | 298031069141856 |
[1,2,6,23,99,452,2136,10313,50469,249062,1235466, 6147803,30650439,152986472,764135196,3818284493, 19084248009,95399716682,476934013326, 2384476356383,11921800651179,59607259863692, 298031069141856] |