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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 43 |
| 4 | 393 |
| 5 | 4721 |
| 6 | 69853 |
| 7 | 1225757 |
| 8 | 24866481 |
| 9 | 572410513 |
| 10 | 14738647221 |
| 11 | 419682895325 |
| 12 | 13094075689225 |
| 13 | 444198818128313 |
| 14 | 16278315877572141 |
| 15 | 640854237634448101 |
| 16 | 26973655480577228769 |
| 17 | 1208724395795734172705 |
| 18 | 57453178877303382607717 |
| 19 | 2887169565412587866031533 |
[1,2,7,43,393,4721,69853,1225757,24866481, 572410513,14738647221,419682895325,13094075689225, 444198818128313,16278315877572141, 640854237634448101,26973655480577228769, 1208724395795734172705,57453178877303382607717, 2887169565412587866031533] |