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 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 47 |
| 5 | 207 |
| 6 | 2249 |
| 7 | 14501 |
| 8 | 216273 |
| 9 | 1830449 |
| 10 | 34662523 |
| 11 | 362983263 |
| 12 | 8330310559 |
| 13 | 103938238111 |
| 14 | 2801976629841 |
| 15 | 40574514114061 |
| 16 | 1256354802202337 |
| 17 | 20708839411614753 |
| 18 | 724160187180691379 |
| 19 | 13386284447024070647 |