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| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 9 |
| 3 | 15 |
| 4 | 54 |
| 5 | 290 |
| 6 | 987 |
| 7 | 4530 |
| 8 | 21481 |
| 9 | 58554 |
| 10 | 60967 |
| 11 | 136457 |
| 12 | 136456 |
| 13 | 673393 |
| 14 | 1254204 |
| 15 | 1254203 |
| 16 | 7709873 |
| 17 | 21357254 |
| 18 | 21357253 |
| 19 | 25813465 |
| 20 | 25813464 |
| 21 | 39500858 |
| 22 | 39500857 |
| 23 | 947438661 |
| 24 | 947438660 |
| 25 | 947438659 |
| 26 | 5703167679 |
| 27 | 5703167678 |
| 28 | 16976360924 |
| 29 | 68745739764 |
| 30 | 117327812949 |
| 31 | 198156183037 |
[3,9,15,54,290,987,4530,21481,58554,60967,136457, 136456,673393,1254204,1254203,7709873,21357254, 21357253,25813465,25813464,39500858,39500857, 947438661,947438660,947438659,5703167679, 5703167678,16976360924,68745739764,117327812949, 198156183037] |