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 | 18 |
| 2 | 189 |
| 3 | 1482 |
| 4 | 9576 |
| 5 | 53676 |
| 6 | 269325 |
| 7 | 1235286 |
| 8 | 5256711 |
| 9 | 20985272 |
| 10 | 79260723 |
| 11 | 285139764 |
| 12 | 982349361 |
| 13 | 3255488082 |
| 14 | 10416507579 |
| 15 | 32281134120 |
| 16 | 97154549289 |
| 17 | 284625019800 |
| 18 | 813310723925 |
| 19 | 2270826800172 |
| 20 | 6204926551824 |
| 21 | 16615751700618 |