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 | 0 |
| 2 | 1 |
| 3 | 5 |
| 4 | 24 |
| 5 | 229 |
| 6 | 3436 |
| 7 | 65772 |
| 8 | 1743247 |
| 9 | 78586742 |
| 10 | 7234839185 |
| 11 | 1330059590925 |
| 12 | 421587920205546 |
| 13 | 212201572752086670 |
| 14 | 170288846375423693683 |
| 15 | 227570453486998336648738 |
| 16 | 527014715702923506908210573 |
| 17 | 2140337449056844246626590305042 |
| 18 | 15055309813180236733267168372538873 |