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 | 2 |
| 2 | 6 |
| 3 | 28 |
| 4 | 199 |
| 5 | 1945 |
| 6 | 24284 |
| 7 | 369007 |
| 8 | 6606841 |
| 9 | 136189033 |
| 10 | 3176299055 |
| 11 | 82687352399 |
| 12 | 2376681846391 |
| 13 | 74755785129007 |
| 14 | 2554042404290937 |
| 15 | 94185081322401217 |
| 16 | 3728691027764891142 |
| 17 | 157729043279607820306 |
| 18 | 7100056927514281702122 |
| 19 | 338867203461763515919479 |