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| n | a(n) |
|---|---|
| 1 | 7 |
| 2 | 63 |
| 3 | 511 |
| 4 | 4095 |
| 5 | 32753 |
| 6 | 262017 |
| 7 | 2096129 |
| 8 | 16769025 |
| 9 | 134152151 |
| 10 | 1073216767 |
| 11 | 8585730559 |
| 12 | 68685815807 |
| 13 | 549486297185 |
| 14 | 4395888543361 |
| 15 | 35167093673985 |
| 16 | 281336632008705 |
| 17 | 2250692117004583 |
| 18 | 18005529423519295 |
| 19 | 144044175288040447 |
[7,63,511,4095,32753,262017,2096129,16769025, 134152151,1073216767,8585730559,68685815807, 549486297185,4395888543361,35167093673985, 281336632008705,2250692117004583, 18005529423519295,144044175288040447] |