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 | 0 |
| 1 | 23 |
| 2 | 111 |
| 3 | 479 |
| 4 | 1471 |
| 5 | 6015 |
| 6 | 24319 |
| 7 | 28415 |
| 8 | 114175 |
| 9 | 457727 |
| 10 | 490495 |
| 11 | 1964031 |
| 12 | 6025215 |
| 13 | 8122367 |
| 14 | 32497663 |
| 15 | 98549759 |
| 16 | 132104191 |
| 17 | 528449535 |
| 18 | 1593769983 |
| 19 | 1862205439 |
| 20 | 7448952831 |
| 21 | 25635323903 |
| 22 | 29930291199 |
| 23 | 119721689087 |
| 24 | 411242070015 |
| 25 | 479961546751 |
| 26 | 514321285119 |
| 27 | 2057287237631 |
| 28 | 7687987265535 |