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| n | a(n) |
|---|---|
| 1 | 7 |
| 2 | 49 |
| 3 | 149 |
| 4 | 585 |
| 5 | 3639 |
| 6 | 23977 |
| 7 | 129481 |
| 8 | 762529 |
| 9 | 4977703 |
| 10 | 33121201 |
| 11 | 212297621 |
| 12 | 1392648681 |
| 13 | 9394847463 |
| 14 | 63791220457 |
| 15 | 431043859993 |
| 16 | 2933293326289 |
| 17 | 20157021722983 |
| 18 | 138871827073201 |
| 19 | 957160775849621 |
| 20 | 6614231267870601 |
[7,49,149,585,3639,23977,129481,762529,4977703, 33121201,212297621,1392648681,9394847463, 63791220457,431043859993,2933293326289, 20157021722983,138871827073201,957160775849621, 6614231267870601] |