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 | 13 |
| 3 | 61 |
| 4 | 281 |
| 5 | 1261 |
| 6 | 5545 |
| 7 | 24025 |
| 8 | 102961 |
| 9 | 437581 |
| 10 | 1847561 |
| 11 | 7759753 |
| 12 | 32449873 |
| 13 | 135207801 |
| 14 | 561632401 |
| 15 | 2326762801 |
| 16 | 9617286241 |
| 17 | 39671305741 |
| 18 | 163352435401 |
| 19 | 671560012201 |
| 20 | 2756930576401 |
| 21 | 11303415363241 |
| 22 | 46290177201841 |
| 23 | 189368906734801 |
| 24 | 773942488394401 |