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 | 1 |
| 2 | 5 |
| 3 | 17 |
| 4 | 105 |
| 5 | 433 |
| 6 | 2925 |
| 7 | 13185 |
| 8 | 93425 |
| 9 | 443009 |
| 10 | 3233205 |
| 11 | 15840209 |
| 12 | 117950745 |
| 13 | 591187953 |
| 14 | 4466545245 |
| 15 | 22766535297 |
| 16 | 173906505825 |
| 17 | 897941153665 |
| 18 | 6918379345125 |
| 19 | 36089242700049 |
| 20 | 279988660639305 |
| 21 | 1472715584804529 |
| 22 | 11490841104036045 |
| 23 | 60857608450349313 |
| 24 | 477104721264920145 |