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 | 10 |
| 4 | 30 |
| 5 | 56 |
| 6 | -167 |
| 7 | -2813 |
| 8 | -21515 |
| 9 | -126135 |
| 10 | -601812 |
| 11 | -2179039 |
| 12 | -3455504 |
| 13 | 32238155 |
| 14 | 430944400 |
| 15 | 3334419890 |
| 16 | 20083350422 |
| 17 | 97094186751 |
| 18 | 338485665435 |
| 19 | 274332822425 |
| 20 | -8491831747320 |
| 21 | -97735154210032 |
| 22 | -732963337489636 |
| 23 | -4341176221239330 |