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) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 3 |
| 5 | 11 |
| 6 | 60 |
| 7 | 502 |
| 8 | 7403 |
| 9 | 197442 |
| 10 | 9804368 |
| 11 | 902818087 |
| 12 | 153721215608 |
| 13 | 48443044675155 |
| 14 | 28363687700395422 |
| 15 | 30996524108446916915 |
| 16 | 63502033750022111383196 |
| 17 | 244852545022627009655180986 |
| 18 | 1783161611023802810566806448531 |
| 19 | 24603891215865809635944516464394339 |