This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 9 |
| 3 | 35 |
| 4 | 135 |
| 5 | 527 |
| 6 | 2079 |
| 7 | 8255 |
| 8 | 32895 |
| 9 | 131327 |
| 10 | 524799 |
| 11 | 2098175 |
| 12 | 8390655 |
| 13 | 33558527 |
| 14 | 134225919 |
| 15 | 536887295 |
| 16 | 2147516415 |
| 17 | 8590000127 |
| 18 | 34359869439 |
| 19 | 137439215615 |
| 20 | 549756338175 |
| 21 | 2199024304127 |
| 22 | 8796095119359 |
| 23 | 35184376283135 |
| 24 | 140737496743935 |
| 25 | 562949970198527 |