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) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 9 |
| 3 | 31 |
| 4 | 117 |
| 5 | 459 |
| 6 | 1825 |
| 7 | 7287 |
| 8 | 29133 |
| 9 | 116515 |
| 10 | 466041 |
| 11 | 1864143 |
| 12 | 7456549 |
| 13 | 29826171 |
| 14 | 119304657 |
| 15 | 477218599 |
| 16 | 1908874365 |
| 17 | 7635497427 |
| 18 | 30541989673 |
| 19 | 122167958655 |
| 20 | 488671834581 |
| 21 | 1954687338283 |
| 22 | 7818749353089 |
| 23 | 31274997412311 |