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 | 11 |
| 2 | 67 |
| 3 | 503 |
| 4 | 3939 |
| 5 | 31111 |
| 6 | 246163 |
| 7 | 1948503 |
| 8 | 15424707 |
| 9 | 122107175 |
| 10 | 966645747 |
| 11 | 7652334327 |
| 12 | 60578794275 |
| 13 | 479564842183 |
| 14 | 3796418256467 |
| 15 | 30053895424663 |
| 16 | 237918103255427 |
| 17 | 1883450483360871 |
| 18 | 14910112659965107 |
| 19 | 118034140795537975 |
| 20 | 934403294669416419 |
| 21 | 7397093003809879047 |