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 | 4 |
| 2 | 30 |
| 3 | 280 |
| 4 | 2940 |
| 5 | 33264 |
| 6 | 396396 |
| 7 | 4907760 |
| 8 | 62573940 |
| 9 | 816621520 |
| 10 | 10861066216 |
| 11 | 146738321184 |
| 12 | 2008917492400 |
| 13 | 27815780664000 |
| 14 | 388924218927000 |
| 15 | 5484594083378400 |
| 16 | 77926940934668100 |
| 17 | 1114620641232714000 |