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 | 7 |
| 2 | 13 |
| 3 | 97 |
| 4 | 193 |
| 5 | 769 |
| 6 | 1531 |
| 7 | 3049 |
| 8 | 6073 |
| 9 | 12097 |
| 10 | 24097 |
| 11 | 95617 |
| 12 | 379399 |
| 13 | 2998753 |
| 14 | 187339729 |
| 15 | 373174033 |
| 16 | 2949551617 |
| 17 | 184265983633 |
| 18 | 731152932481 |
| 19 | 88025699967469825543 |
| 20 | 175344042716296888429 |
| 21 | 4979552865927484193343796114081304399449 |