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| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 2 |
| 4 | 6 |
| 5 | 19 |
| 6 | 78 |
| 7 | 387 |
| 8 | 2327 |
| 9 | 16384 |
| 10 | 132336 |
| 11 | 1203145 |
| 12 | 12146959 |
| 13 | 134749221 |
| 14 | 1628840129 |
| 15 | 21308361378 |
| 16 | 299940041508 |
| 17 | 4520381905248 |
| 18 | 72625922986869 |
| 19 | 1239160455312246 |
| 20 | 22377511072312218 |
| 21 | 426411855436193451 |
| 22 | 8550614540544797370 |
| 23 | 179989316790109543775 |
| 24 | 3968315581691624472787 |
| 25 | 91451247683519227059456 |
[1,2,6,19,78,387,2327,16384,132336,1203145, 12146959,134749221,1628840129,21308361378, 299940041508,4520381905248,72625922986869, 1239160455312246,22377511072312218, 426411855436193451,8550614540544797370, 179989316790109543775,3968315581691624472787, 91451247683519227059456] |