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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 12 |
| 5 | 27 |
| 6 | 103 |
| 7 | 391 |
| 8 | 1383 |
| 9 | 6260 |
| 10 | 32704 |
| 11 | 149045 |
| 12 | 812696 |
| 13 | 5034682 |
| 14 | 27895385 |
| 15 | 173642918 |
| 16 | 1221049609 |
| 17 | 7859267162 |
| 18 | 54735567331 |
| 19 | 426299653269 |
| 20 | 3100614554854 |
| 21 | 23801458978807 |
| 22 | 202181105885405 |
| 23 | 1629802507466471 |
| 24 | 13634143960693703 |
| 25 | 124940706768934047 |
[1,2,4,12,27,103,391,1383,6260,32704,149045, 812696,5034682,27895385,173642918,1221049609, 7859267162,54735567331,426299653269,3100614554854, 23801458978807,202181105885405,1629802507466471, 13634143960693703,124940706768934047] |