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 | 2 |
| 3 | 3 |
| 4 | 4 |
| 5 | 7 |
| 6 | 12 |
| 7 | 29 |
| 8 | 84 |
| 9 | 355 |
| 10 | 2038 |
| 11 | 15723 |
| 12 | 156920 |
| 13 | 1959177 |
| 14 | 29788564 |
| 15 | 539206155 |
| 16 | 11406258536 |
| 17 | 277708694711 |
| 18 | 7683630307352 |
| 19 | 239005572292955 |
| 20 | 8281900782667178 |
| 21 | 317172995786425445 |