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 | 21 |
| 2 | 221 |
| 3 | 1561 |
| 4 | 8361 |
| 5 | 36365 |
| 6 | 134245 |
| 7 | 433905 |
| 8 | 1256465 |
| 9 | 3317445 |
| 10 | 8097453 |
| 11 | 18474633 |
| 12 | 39753273 |
| 13 | 81270333 |
| 14 | 158819253 |
| 15 | 298199265 |
| 16 | 540279585 |
| 17 | 948062325 |
| 18 | 1616336765 |
| 19 | 2684641785 |
| 20 | 4354393801 |
| 21 | 6911195501 |
| 22 | 10753517061 |
| 23 | 16429137361 |
| 24 | 24680949041 |
| 25 | 36503969061 |