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| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 27 |
| 3 | 240 |
| 4 | 2127 |
| 5 | 18828 |
| 6 | 166581 |
| 7 | 1473549 |
| 8 | 13033908 |
| 9 | 115285587 |
| 10 | 1019699649 |
| 11 | 9019211256 |
| 12 | 79774585647 |
| 13 | 705603080553 |
| 14 | 6241031204616 |
| 15 | 55201672045839 |
| 16 | 488256584905473 |
| 17 | 4318609990477032 |
| 18 | 38197932848425719 |
| 19 | 337859190101460441 |
[3,27,240,2127,18828,166581,1473549,13033908, 115285587,1019699649,9019211256,79774585647, 705603080553,6241031204616,55201672045839, 488256584905473,4318609990477032, 38197932848425719,337859190101460441] |