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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 7 |
| 3 | 35 |
| 4 | 178 |
| 5 | 891 |
| 6 | 4457 |
| 7 | 22285 |
| 8 | 111428 |
| 9 | 557141 |
| 10 | 2785707 |
| 11 | 13928535 |
| 12 | 69642678 |
| 13 | 348213391 |
| 14 | 1741066957 |
| 15 | 8705334785 |
| 16 | 43526673928 |
| 17 | 217633369641 |
| 18 | 1088166848207 |
| 19 | 5440834241035 |
| 20 | 27204171205178 |
| 21 | 136020856025891 |
| 22 | 680104280129457 |
[1,7,35,178,891,4457,22285,111428,557141,2785707, 13928535,69642678,348213391,1741066957,8705334785, 43526673928,217633369641,1088166848207, 5440834241035,27204171205178,136020856025891, 680104280129457] |